Systems and methods for providing a virtual appliance in an application delivery fabric

ABSTRACT

The present disclosure is directed to systems and method for providing a virtual appliance. One or more application delivery controller appliances intermediary to a plurality of clients and a plurality of servers perform a plurality of application delivery control functions on network traffic communicated between the plurality of clients and the plurality of servers. A virtual application delivery controller is deployed on a device intermediary to the plurality of clients and the plurality of servers. The virtual application delivery controller executing on the device performs one or more of the plurality of application delivery control functions on network traffic communicated between the plurality of clients and the plurality of servers.

RELATED APPLICATION

This application is a continuation of and claims priority to, and thebenefit of, U.S. Non-provisional application Ser. No. 12/771,580,entitled “Systems And Methods For Providing A Virtual Appliance In AnApplication Delivery Fabric” and filed on Apr. 30, 2010, now U.S. Pat.No. 8,868,724, which claims priority to, and the benefit of, and is anon-provisional of U.S. Provisional Application No. 61/174,699, “Systemsand Methods for Providing a Virtual Appliance in an Application DeliveryFabric,” filed on May 1, 2009, all of which are incorporated herein byreference in their entirety for all purposes.

FIELD OF THE INVENTION

The present application generally relates to application deliverycontrollers. In particular, the present application relates to systemsand methods for providing one or more virtual application deliverycontrollers in an application delivery fabric.

BACKGROUND

Providing an application delivery fabric (ADF) whose capacity matchesdemands for resources presents a challenging dilemma. An ADF designermust estimate an expected level of demand for resources and purchase thecorresponding number of application delivery controllers to service thisdemand, and each of the application delivery controllers can beexpensive. If the purchased application delivery controllers cannotservice demands for resources, the ADF can become overloaded, resultingin a drop in performance. As a result, additional controllers may needto be purchased. However, should demand drop, controllers in the fabricmay be left idle. In this manner, an application delivery fabric canprove to be insufficient for network needs or inefficiently used.

SUMMARY

In the present disclosure, application delivery controllers may bevirtualized and deployed in response to ADF demands. A command centermay monitor the loads of virtual application delivery controllers. Ifperformance-related metrics of the virtual application deliverycontrollers indicate the controllers are reaching their capacity orexperiencing degradation in performance, the command center may deployadditional virtual application delivery controllers in response.Further, if the same metrics indicate that demand has dropped, thecommand center may determine if loads may be consolidated on a fewernumber of virtual controllers. Then, the command center may undeployvirtual application delivery controllers, thereby making resourcesavailable for other uses.

In one aspect, the present disclosure is directed to a method fordeploying a virtual application delivery controller. The method includesperforming, by one or more application delivery controller appliancesintermediary to a plurality of clients and a plurality of servers, aplurality of application delivery control functions on network trafficcommunicated between the plurality of clients and the plurality ofservers. The method also includes deploying a virtual applicationdelivery controller on a device intermediary to the plurality of clientsand the plurality of servers. The method also includes performing, bythe virtual application delivery controller executing on the device, oneor more of the plurality of application delivery control functions onnetwork traffic communicated between the plurality of clients and theplurality of servers.

The virtual application delivery controller may be deployed in avirtualized environment provided by the device. The virtual applicationdelivery controller may be deployed to execute on a virtual machineprovided by the device. The virtual application delivery controller maybe deployed to execute as a virtual machine on the device. A cloudservice may be requested to execute the virtual application deliverycontroller on resources provided by the cloud service. The virtualapplication delivery controller may be installed to execute in anon-virtualized environment of the device. A centralized command centermay determine to deploy the virtual application delivery controller. Theone or more of the plurality of application delivery control functionsfor the virtual application delivery controller may be configured fordeployment. The virtual application delivery controller may perform theone or more of the plurality of application delivery control functionson a first portion of network traffic concurrently to the one or moreapplication delivery controller appliances performing the plurality ofapplication delivery control functions on a second portion of networktraffic. The virtual application delivery controller may perform a firstapplication delivery control function on a first portion of networktraffic subsequent to an application delivery controller applianceperforming a second application delivery control function on the firstportion of network traffic.

In another aspect, the present disclosure is directed to a method formanaging a plurality of application delivery controllers of anapplication delivery network. The method includes monitoring, by anapplication delivery fabric (ADF) manager executing on a device, anapplication delivery fabric (ADF) network comprising a deployment of aplurality of application delivery controllers intermediary to aplurality of a clients and a plurality of servers. The method alsoincludes determining, by the ADF manager responsive to monitoring, thatan operational or performance characteristic of the ADF network fails acorresponding threshold. The method also includes dynamically deploying,by the ADF manager responsive to the determination, a virtualapplication delivery controller as part of the ADF network.

The ADF manager may establish one or more application deliverycontroller appliances as part of the ADF network. The ADF manager mayestablish one or more virtual application delivery controllers as partof the ADF network. The ADF manager may determine, responsive tomonitoring, that a number of users of the plurality of applicationdelivery controllers exceeds a threshold. The ADF manager may determine,responsive to monitoring, that a number of connection of the pluralityof application delivery controllers exceeds a threshold. The ADF managermay determine, responsive to monitoring, that response times of serversvia the plurality of application delivery controllers exceeds athreshold. The ADF manager may determine, responsive to monitoring, thatone of a bandwidth or transmission rates via the plurality ofapplication delivery controllers exceeds a threshold. A cloud servicemay dynamically deploy the virtual application delivery controller. Avirtual application delivery controller may be undeployed from the ADFnetwork responsive to monitoring.

BRIEF DESCRIPTION OF THE FIGURES BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent and better understood byreferring to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1A is a block diagram of an embodiment of a network environment fora client to access a server via an appliance;

FIG. 1B is a block diagram of an embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIG. 1C is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIG. 1D is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIGS. 1E-1H are block diagrams of embodiments of a computing device;

FIG. 2A is a block diagram of an embodiment of an appliance forprocessing communications between a client and a server;

FIG. 2B is a block diagram of another embodiment of an appliance foroptimizing, accelerating, load-balancing and routing communicationsbetween a client and a server;

FIG. 3A is a block diagram of an embodiment of a virtualizationenvironment;

FIG. 3B is a block diagram of another embodiment of a virtualizationenvironment;

FIG. 4A is a block diagram of an embodiment of a virtualized appliance;

FIG. 4B is a block diagram of another embodiment of a virtualizedappliance;

FIG. 5A is a block diagram of an embodiment of a application deliveryfabric;

FIG. 5B is a block diagram of another embodiment of a applicationdelivery fabric;

FIG. 6 is a block diagram of an embodiment of a multi-tenantenvironment;

FIG. 7 is a block diagram of an embodiment of a cloud balancing;

FIG. 8 is a flow diagram depicting an embodiment of a method ofdeploying a virtual application delivery controller; and

FIG. 9 is a flow diagram depicting an embodiment of managing a pluralityof application delivery controllers of an application delivery network.

The features and advantages of the present invention will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, in which like reference charactersidentify corresponding elements throughout. In the drawings, likereference numbers generally indicate identical, functionally similar,and/or structurally similar elements.

DETAILED DESCRIPTION OF THE INVENTION

A. Network and Computing Environment

Prior to discussing the specifics of embodiments of the systems andmethods of an appliance and/or client, it may be helpful to discuss thenetwork and computing environments in which such embodiments may bedeployed. Referring now to FIG. 1A, an embodiment of a networkenvironment is depicted. In brief overview, the network environmentcomprises one or more clients 102 a-102 n (also generally referred to aslocal machine(s) 102, or client(s) 102) in communication with one ormore servers 106 a-106 n (also generally referred to as server(s) 106,or remote machine(s) 106) via one or more networks 104, 104′ (generallyreferred to as network 104). In some embodiments, a client 102communicates with a server 106 via an appliance 200.

Although FIG. 1A shows a network 104 and a network 104′ between theclients 102 and the servers 106, the clients 102 and the servers 106 maybe on the same network 104. The networks 104 and 104′ can be the sametype of network or different types of networks. The network 104 and/orthe network 104′ can be a local-area network (LAN), such as a companyIntranet, a metropolitan area network (MAN), or a wide area network(WAN), such as the Internet or the World Wide Web. In one embodiment,network 104′ may be a private network and network 104 may be a publicnetwork. In some embodiments, network 104 may be a private network andnetwork 104′ a public network. In another embodiment, networks 104 and104′ may both be private networks. In some embodiments, clients 102 maybe located at a branch office of a corporate enterprise communicatingvia a WAN connection over the network 104 to the servers 106 located ata corporate data center.

The network 104 and/or 104′ may be any type and/or form of network andmay include any of the following: a point to point network, a broadcastnetwork, a wide area network, a local area network, a telecommunicationsnetwork, a data communication network, a computer network, an ATM(Asynchronous Transfer Mode) network, a SONET (Synchronous OpticalNetwork) network, a SDH (Synchronous Digital Hierarchy) network, awireless network and a wireline network. In some embodiments, thenetwork 104 may comprise a wireless link, such as an infrared channel orsatellite band. The topology of the network 104 and/or 104′ may be abus, star, or ring network topology. The network 104 and/or 104′ andnetwork topology may be of any such network or network topology as knownto those ordinarily skilled in the art capable of supporting theoperations described herein.

As shown in FIG. 2A, the appliance 200, which also may be referred to asan interface unit 200 or gateway 200, is shown between the networks 104and 104′. In some embodiments, the appliance 200 may be located onnetwork 104. For example, a branch office of a corporate enterprise maydeploy an appliance 200 at the branch office. In other embodiments, theappliance 200 may be located on network 104′. For example, an appliance200 may be located at a corporate data center. In yet anotherembodiment, a plurality of appliances 200 may be deployed on network104. In some embodiments, a plurality of appliances 200 may be deployedon network 104′. In one embodiment, a first appliance 200 communicateswith a second appliance 200′. In other embodiments, the appliance 200could be a part of any client 102 or server 106 on the same or differentnetwork 104,104′ as the client 102. One or more appliances 200 may belocated at any point in the network or network communications pathbetween a client 102 and a server 106.

In some embodiments, the appliance 200 comprises any of the networkdevices manufactured by Citrix Systems, Inc. of Ft. Lauderdale Fla.,referred to as Citrix NetScaler devices. In other embodiments, theappliance 200 includes any of the product embodiments referred to asWebAccelerator and BigIP manufactured by F5 Networks, Inc. of Seattle,Wash. In another embodiment, the appliance 200 includes any of the DXacceleration device platforms and/or the SSL VPN series of devices, suchas SA 700, SA 2000, SA 4000, and SA 6000 devices manufactured by JuniperNetworks, Inc. of Sunnyvale, Calif. In yet another embodiment, theappliance 200 includes any application acceleration and/or securityrelated appliances and/or software manufactured by Cisco Systems, Inc.of San Jose, Calif., such as the Cisco ACE Application Control EngineModule service software and network modules, and Cisco AVS SeriesApplication Velocity System.

In one embodiment, the system may include multiple, logically-groupedservers 106. In these embodiments, the logical group of servers may bereferred to as a server farm 38. In some of these embodiments, theserves 106 may be geographically dispersed. In some cases, a farm 38 maybe administered as a single entity. In other embodiments, the serverfarm 38 comprises a plurality of server farms 38. In one embodiment, theserver farm executes one or more applications on behalf of one or moreclients 102.

The servers 106 within each farm 38 can be heterogeneous. One or more ofthe servers 106 can operate according to one type of operating systemplatform (e.g., WINDOWS NT, manufactured by Microsoft Corp. of Redmond,Wash.), while one or more of the other servers 106 can operate onaccording to another type of operating system platform (e.g., Unix orLinux). The servers 106 of each farm 38 do not need to be physicallyproximate to another server 106 in the same farm 38. Thus, the group ofservers 106 logically grouped as a farm 38 may be interconnected using awide-area network (WAN) connection or medium-area network (MAN)connection. For example, a farm 38 may include servers 106 physicallylocated in different continents or different regions of a continent,country, state, city, campus, or room. Data transmission speeds betweenservers 106 in the farm 38 can be increased if the servers 106 areconnected using a local-area network (LAN) connection or some form ofdirect connection.

Servers 106 may be referred to as a file server, application server, webserver, proxy server, or gateway server. In some embodiments, a server106 may have the capacity to function as either an application server oras a master application server. In one embodiment, a server 106 mayinclude an Active Directory. The clients 102 may also be referred to asclient nodes or endpoints. In some embodiments, a client 102 has thecapacity to function as both a client node seeking access toapplications on a server and as an application server providing accessto hosted applications for other clients 102 a-102 n.

In some embodiments, a client 102 communicates with a server 106. In oneembodiment, the client 102 communicates directly with one of the servers106 in a farm 38. In another embodiment, the client 102 executes aprogram neighborhood application to communicate with a server 106 in afarm 38. In still another embodiment, the server 106 provides thefunctionality of a master node. In some embodiments, the client 102communicates with the server 106 in the farm 38 through a network 104.Over the network 104, the client 102 can, for example, request executionof various applications hosted by the servers 106 a-106 n in the farm 38and receive output of the results of the application execution fordisplay. In some embodiments, only the master node provides thefunctionality required to identify and provide address informationassociated with a server 106′ hosting a requested application.

In one embodiment, the server 106 provides functionality of a webserver. In another embodiment, the server 106 a receives requests fromthe client 102, forwards the requests to a second server 106 b andresponds to the request by the client 102 with a response to the requestfrom the server 106 b. In still another embodiment, the server 106acquires an enumeration of applications available to the client 102 andaddress information associated with a server 106 hosting an applicationidentified by the enumeration of applications. In yet anotherembodiment, the server 106 presents the response to the request to theclient 102 using a web interface. In one embodiment, the client 102communicates directly with the server 106 to access the identifiedapplication. In another embodiment, the client 102 receives applicationoutput data, such as display data, generated by an execution of theidentified application on the server 106.

Referring now to FIG. 1B, an embodiment of a network environmentdeploying multiple appliances 200 is depicted. A first appliance 200 maybe deployed on a first network 104 and a second appliance 200′ on asecond network 104′. For example a corporate enterprise may deploy afirst appliance 200 at a branch office and a second appliance 200′ at adata center. In another embodiment, the first appliance 200 and secondappliance 200′ are deployed on the same network 104 or network 104. Forexample, a first appliance 200 may be deployed for a first server farm38, and a second appliance 200 may be deployed for a second server farm38′. In another example, a first appliance 200 may be deployed at afirst branch office while the second appliance 200′ is deployed at asecond branch office′. In some embodiments, the first appliance 200 andsecond appliance 200′ work in cooperation or in conjunction with eachother to accelerate network traffic or the delivery of application anddata between a client and a server

Referring now to FIG. 1C, another embodiment of a network environmentdeploying the appliance 200 with one or more other types of appliances,such as between one or more WAN optimization appliance 205, 205′ isdepicted. For example a first WAN optimization appliance 205 is shownbetween networks 104 and 104′ and s second WAN optimization appliance205′ may be deployed between the appliance 200 and one or more servers106. By way of example, a corporate enterprise may deploy a first WANoptimization appliance 205 at a branch office and a second WANoptimization appliance 205′ at a data center. In some embodiments, theappliance 205 may be located on network 104′. In other embodiments, theappliance 205′ may be located on network 104. In some embodiments, theappliance 205′may be located on network 104′ or network 104″. In oneembodiment, the appliance 205 and 205′ are on the same network. Inanother embodiment, the appliance 205 and 205′ are on differentnetworks. In another example, a first WAN optimization appliance 205 maybe deployed for a first server farm 38 and a second WAN optimizationappliance 205′ for a second server farm 38′

In one embodiment, the appliance 205 is a device for accelerating,optimizing or otherwise improving the performance, operation, or qualityof service of any type and form of network traffic, such as traffic toand/or from a WAN connection. In some embodiments, the appliance 205 isa performance enhancing proxy. In other embodiments, the appliance 205is any type and form of WAN optimization or acceleration device,sometimes also referred to as a WAN optimization controller. In oneembodiment, the appliance 205 is any of the product embodiments referredto as WANScaler manufactured by Citrix Systems, Inc. of Ft. Lauderdale,Fla. In other embodiments, the appliance 205 includes any of the productembodiments referred to as BIG-IP link controller and WANjetmanufactured by F5 Networks, Inc. of Seattle, Wash. In anotherembodiment, the appliance 205 includes any of the WX and WXC WANacceleration device platforms manufactured by Juniper Networks, Inc. ofSunnyvale, Calif. In some embodiments, the appliance 205 includes any ofthe steelhead line of WAN optimization appliances manufactured byRiverbed Technology of San Francisco, Calif. In other embodiments, theappliance 205 includes any of the WAN related devices manufactured byExpand Networks Inc. of Roseland, N.J. In one embodiment, the appliance205 includes any of the WAN related appliances manufactured by PacketeerInc. of Cupertino, Calif., such as the PacketShaper, iShared, and SkyXproduct embodiments provided by Packeteer. In yet another embodiment,the appliance 205 includes any WAN related appliances and/or softwaremanufactured by Cisco Systems, Inc. of San Jose, Calif., such as theCisco Wide Area Network Application Services software and networkmodules, and Wide Area Network engine appliances.

In one embodiment, the appliance 205 provides application and dataacceleration services for branch-office or remote offices. In oneembodiment, the appliance 205 includes optimization of Wide Area FileServices (WAFS). In another embodiment, the appliance 205 acceleratesthe delivery of files, such as via the Common Internet File System(CIFS) protocol. In other embodiments, the appliance 205 providescaching in memory and/or storage to accelerate delivery of applicationsand data. In one embodiment, the appliance 205 provides compression ofnetwork traffic at any level of the network stack or at any protocol ornetwork layer. In another embodiment, the appliance 205 providestransport layer protocol optimizations, flow control, performanceenhancements or modifications and/or management to accelerate deliveryof applications and data over a WAN connection. For example, in oneembodiment, the appliance 205 provides Transport Control Protocol (TCP)optimizations. In other embodiments, the appliance 205 providesoptimizations, flow control, performance enhancements or modificationsand/or management for any session or application layer protocol.

In another embodiment, the appliance 205 encoded any type and form ofdata or information into custom or standard TCP and/or IP header fieldsor option fields of network packet to announce presence, functionalityor capability to another appliance 205′. In another embodiment, anappliance 205′ may communicate with another appliance 205′ using dataencoded in both TCP and/or IP header fields or options. For example, theappliance may use TCP option(s) or IP header fields or options tocommunicate one or more parameters to be used by the appliances 205,205′ in performing functionality, such as WAN acceleration, or forworking in conjunction with each other.

In some embodiments, the appliance 200 preserves any of the informationencoded in TCP and/or IP header and/or option fields communicatedbetween appliances 205 and 205′. For example, the appliance 200 mayterminate a transport layer connection traversing the appliance 200,such as a transport layer connection from between a client and a servertraversing appliances 205 and 205′. In one embodiment, the appliance 200identifies and preserves any encoded information in a transport layerpacket transmitted by a first appliance 205 via a first transport layerconnection and communicates a transport layer packet with the encodedinformation to a second appliance 205′ via a second transport layerconnection.

Referring now to FIG. 1D, a network environment for delivering and/oroperating a computing environment on a client 102 is depicted. In someembodiments, a server 106 includes an application delivery system 190for delivering a computing environment or an application and/or datafile to one or more clients 102. In brief overview, a client 10 is incommunication with a server 106 via network 104, 104′ and appliance 200.For example, the client 102 may reside in a remote office of a company,e.g., a branch office, and the server 106 may reside at a corporate datacenter. The client 102 comprises a client agent 120, and a computingenvironment 15. The computing environment 15 may execute or operate anapplication that accesses, processes or uses a data file. The computingenvironment 15, application and/or data file may be delivered via theappliance 200 and/or the server 106.

In some embodiments, the appliance 200 accelerates delivery of acomputing environment 15, or any portion thereof, to a client 102. Inone embodiment, the appliance 200 accelerates the delivery of thecomputing environment 15 by the application delivery system 190. Forexample, the embodiments described herein may be used to acceleratedelivery of a streaming application and data file processable by theapplication from a central corporate data center to a remote userlocation, such as a branch office of the company. In another embodiment,the appliance 200 accelerates transport layer traffic between a client102 and a server 106. The appliance 200 may provide accelerationtechniques for accelerating any transport layer payload from a server106 to a client 102, such as: 1) transport layer connection pooling, 2)transport layer connection multiplexing, 3) transport control protocolbuffering, 4) compression and 5) caching. In some embodiments, theappliance 200 provides load balancing of servers 106 in responding torequests from clients 102. In other embodiments, the appliance 200 actsas a proxy or access server to provide access to the one or more servers106. In another embodiment, the appliance 200 provides a secure virtualprivate network connection from a first network 104 of the client 102 tothe second network 104′ of the server 106, such as an SSL VPNconnection. It yet other embodiments, the appliance 200 providesapplication firewall security, control and management of the connectionand communications between a client 102 and a server 106.

In some embodiments, the application delivery management system 190provides application delivery techniques to deliver a computingenvironment to a desktop of a user, remote or otherwise, based on aplurality of execution methods and based on any authentication andauthorization policies applied via a policy engine 195. With thesetechniques, a remote user may obtain a computing environment and accessto server stored applications and data files from any network connecteddevice 100. In one embodiment, the application delivery system 190 mayreside or execute on a server 106. In another embodiment, theapplication delivery system 190 may reside or execute on a plurality ofservers 106 a-106 n. In some embodiments, the application deliverysystem 190 may execute in a server farm 38. In one embodiment, theserver 106 executing the application delivery system 190 may also storeor provide the application and data file. In another embodiment, a firstset of one or more servers 106 may execute the application deliverysystem 190, and a different server 106 n may store or provide theapplication and data file. In some embodiments, each of the applicationdelivery system 190, the application, and data file may reside or belocated on different servers. In yet another embodiment, any portion ofthe application delivery system 190 may reside, execute or be stored onor distributed to the appliance 200, or a plurality of appliances.

The client 102 may include a computing environment 15 for executing anapplication that uses or processes a data file. The client 102 vianetworks 104, 104′ and appliance 200 may request an application and datafile from the server 106. In one embodiment, the appliance 200 mayforward a request from the client 102 to the server 106. For example,the client 102 may not have the application and data file stored oraccessible locally. In response to the request, the application deliverysystem 190 and/or server 106 may deliver the application and data fileto the client 102. For example, in one embodiment, the server 106 maytransmit the application as an application stream to operate incomputing environment 15 on client 102.

In some embodiments, the application delivery system 190 comprises anyportion of the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™ and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application delivery system 190 may deliver one ormore applications to clients 102 or users via a remote-display protocolor otherwise via remote-based or server-based computing. In anotherembodiment, the application delivery system 190 may deliver one or moreapplications to clients or users via streaming of the application.

In one embodiment, the application delivery system 190 includes a policyengine 195 for controlling and managing the access to, selection ofapplication execution methods and the delivery of applications. In someembodiments, the policy engine 195 determines the one or moreapplications a user or client 102 may access. In another embodiment, thepolicy engine 195 determines how the application should be delivered tothe user or client 102, e.g., the method of execution. In someembodiments, the application delivery system 190 provides a plurality ofdelivery techniques from which to select a method of applicationexecution, such as a server-based computing, streaming or delivering theapplication locally to the client 120 for local execution.

In one embodiment, a client 102 requests execution of an applicationprogram and the application delivery system 190 comprising a server 106selects a method of executing the application program. In someembodiments, the server 106 receives credentials from the client 102. Inanother embodiment, the server 106 receives a request for an enumerationof available applications from the client 102. In one embodiment, inresponse to the request or receipt of credentials, the applicationdelivery system 190 enumerates a plurality of application programsavailable to the client 102. The application delivery system 190receives a request to execute an enumerated application. The applicationdelivery system 190 selects one of a predetermined number of methods forexecuting the enumerated application, for example, responsive to apolicy of a policy engine. The application delivery system 190 mayselect a method of execution of the application enabling the client 102to receive application-output data generated by execution of theapplication program on a server 106. The application delivery system 190may select a method of execution of the application enabling the localmachine 10 to execute the application program locally after retrieving aplurality of application files comprising the application. In yetanother embodiment, the application delivery system 190 may select amethod of execution of the application to stream the application via thenetwork 104 to the client 102.

A client 102 may execute, operate or otherwise provide an application,which can be any type and/or form of software, program, or executableinstructions such as any type and/or form of web browser, web-basedclient, client-server application, a thin-client computing client, anActiveX control, or a Java applet, or any other type and/or form ofexecutable instructions capable of executing on client 102. In someembodiments, the application may be a server-based or a remote-basedapplication executed on behalf of the client 102 on a server 106. In oneembodiments the server 106 may display output to the client 102 usingany thin-client or remote-display protocol, such as the IndependentComputing Architecture (ICA) protocol manufactured by Citrix Systems,Inc. of Ft. Lauderdale, Fla. or the Remote Desktop Protocol (RDP)manufactured by the Microsoft Corporation of Redmond, Wash. Theapplication can use any type of protocol and it can be, for example, anHTTP client, an FTP client, an Oscar client, or a Telnet client. Inother embodiments, the application comprises any type of softwarerelated to VoIP communications, such as a soft IP telephone. In furtherembodiments, the application comprises any application related toreal-time data communications, such as applications for streaming videoand/or audio.

In some embodiments, the server 106 or a server farm 38 may be runningone or more applications, such as an application providing a thin-clientcomputing or remote display presentation application. In one embodiment,the server 106 or server farm 38 executes as an application, any portionof the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™, and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application is an ICA client, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla. In other embodiments, theapplication includes a Remote Desktop (RDP) client, developed byMicrosoft Corporation of Redmond, Wash. Also, the server 106 may run anapplication, which for example, may be an application server providingemail services such as Microsoft Exchange manufactured by the MicrosoftCorporation of Redmond, Wash., a web or Internet server, or a desktopsharing server, or a collaboration server. In some embodiments, any ofthe applications may comprise any type of hosted service or products,such as GoToMeeting™ provided by Citrix Online Division, Inc. of SantaBarbara, Calif., WebEx™ provided by WebEx, Inc. of Santa Clara, Calif.,or Microsoft Office Live Meeting provided by Microsoft Corporation ofRedmond, Wash.

Still referring to FIG. 1D, an embodiment of the network environment mayinclude a monitoring server 106A. The monitoring server 106A may includeany type and form performance monitoring service 198. The performancemonitoring service 198 may include monitoring, measurement and/ormanagement software and/or hardware, including data collection,aggregation, analysis, management and reporting. In one embodiment, theperformance monitoring service 198 includes one or more monitoringagents 197. The monitoring agent 197 includes any software, hardware orcombination thereof for performing monitoring, measurement and datacollection activities on a device, such as a client 102, server 106 oran appliance 200, 205. In some embodiments, the monitoring agent 197includes any type and form of script, such as Visual Basic script, orJavascript. In one embodiment, the monitoring agent 197 executestransparently to any application and/or user of the device. In someembodiments, the monitoring agent 197 is installed and operatedunobtrusively to the application or client. In yet another embodiment,the monitoring agent 197 is installed and operated without anyinstrumentation for the application or device.

In some embodiments, the monitoring agent 197 monitors, measures andcollects data on a predetermined frequency. In other embodiments, themonitoring agent 197 monitors, measures and collects data based upondetection of any type and form of event. For example, the monitoringagent 197 may collect data upon detection of a request for a web page orreceipt of an HTTP response. In another example, the monitoring agent197 may collect data upon detection of any user input events, such as amouse click. The monitoring agent 197 may report or provide anymonitored, measured or collected data to the monitoring service 198. Inone embodiment, the monitoring agent 197 transmits information to themonitoring service 198 according to a schedule or a predeterminedfrequency. In another embodiment, the monitoring agent 197 transmitsinformation to the monitoring service 198 upon detection of an event.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of any networkresource or network infrastructure element, such as a client, server,server farm, appliance 200, appliance 205, or network connection. In oneembodiment, the monitoring service 198 and/or monitoring agent 197performs monitoring and performance measurement of any transport layerconnection, such as a TCP or UDP connection. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresnetwork latency. In yet one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures bandwidth utilization.

In other embodiments, the monitoring service 198 and/or monitoring agent197 monitors and measures end-user response times. In some embodiments,the monitoring service 198 performs monitoring and performancemeasurement of an application. In another embodiment, the monitoringservice 198 and/or monitoring agent 197 performs monitoring andperformance measurement of any session or connection to the application.In one embodiment, the monitoring service 198 and/or monitoring agent197 monitors and measures performance of a browser. In anotherembodiment, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of HTTP based transactions. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of a Voice over IP (VoIP) applicationor session. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of a remotedisplay protocol application, such as an ICA client or RDP client. Inyet another embodiment, the monitoring service 198 and/or monitoringagent 197 monitors and measures performance of any type and form ofstreaming media. In still a further embodiment, the monitoring service198 and/or monitoring agent 197 monitors and measures performance of ahosted application or a Software-As-A-Service (SaaS) delivery model.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of one or moretransactions, requests or responses related to application. In otherembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures any portion of an application layer stack, such asany .NET or J2EE calls. In one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures database or SQLtransactions. In yet another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures any method, functionor application programming interface (API) call.

In one embodiment, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of a delivery ofapplication and/or data from a server to a client via one or moreappliances, such as appliance 200 and/or appliance 205. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of delivery of a virtualizedapplication. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of delivery of astreaming application. In another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures performance ofdelivery of a desktop application to a client and/or the execution ofthe desktop application on the client. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresperformance of a client/server application.

In one embodiment, the monitoring service 198 and/or monitoring agent197 is designed and constructed to provide application performancemanagement for the application delivery system 190. For example, themonitoring service 198 and/or monitoring agent 197 may monitor, measureand manage the performance of the delivery of applications via theCitrix Presentation Server. In this example, the monitoring service 198and/or monitoring agent 197 monitors individual ICA sessions. Themonitoring service 198 and/or monitoring agent 197 may measure the totaland per session system resource usage, as well as application andnetworking performance. The monitoring service 198 and/or monitoringagent 197 may identify the active servers for a given user and/or usersession. In some embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors back-end connections between theapplication delivery system 190 and an application and/or databaseserver. The monitoring service 198 and/or monitoring agent 197 maymeasure network latency, delay and volume per user-session or ICAsession.

In some embodiments, the monitoring service 198 and/or monitoring agent197 measures and monitors memory usage for the application deliverysystem 190, such as total memory usage, per user session and/or perprocess. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors CPU usage the applicationdelivery system 190, such as total CPU usage, per user session and/orper process. In another embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors the time required to log-into an application, a server, or the application delivery system, such asCitrix Presentation Server. In one embodiment, the monitoring service198 and/or monitoring agent 197 measures and monitors the duration auser is logged into an application, a server, or the applicationdelivery system 190. In some embodiments, the monitoring service 198and/or monitoring agent 197 measures and monitors active and inactivesession counts for an application, server or application delivery systemsession. In yet another embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors user session latency.

In yet further embodiments, the monitoring service 198 and/or monitoringagent 197 measures and monitors measures and monitors any type and formof server metrics. In one embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors metrics related to systemmemory, CPU usage, and disk storage. In another embodiment, themonitoring service 198 and/or monitoring agent 197 measures and monitorsmetrics related to page faults, such as page faults per second. In otherembodiments, the monitoring service 198 and/or monitoring agent 197measures and monitors round-trip time metrics. In yet anotherembodiment, the monitoring service 198 and/or monitoring agent 197measures and monitors metrics related to application crashes, errorsand/or hangs.

In some embodiments, the monitoring service 198 and monitoring agent 198includes any of the product embodiments referred to as EdgeSightmanufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. In anotherembodiment, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the product embodiments referred to asthe TrueView product suite manufactured by the Symphoniq Corporation ofPalo Alto, Calif. In one embodiment, the performance monitoring service198 and/or monitoring agent 198 includes any portion of the productembodiments referred to as the TeaLeaf CX product suite manufactured bythe TeaLeaf Technology Inc. of San Francisco, Calif. In otherembodiments, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the business service managementproducts, such as the BMC Performance Manager and Patrol products,manufactured by BMC Software, Inc. of Houston, Tex.

The client 102, server 106, and appliance 200 may be deployed as and/orexecuted on any type and form of computing device, such as a computer,network device or appliance capable of communicating on any type andform of network and performing the operations described herein. FIGS. 1Eand 1F depict block diagrams of a computing device 100 useful forpracticing an embodiment of the client 102, server 106 or appliance 200.As shown in FIGS. 1E and 1F, each computing device 100 includes acentral processing unit 101, and a main memory unit 122. As shown inFIG. 1E, a computing device 100 may include a visual display device 124,a keyboard 126 and/or a pointing device 127, such as a mouse. Eachcomputing device 100 may also include additional optional elements, suchas one or more input/output devices 130 a-130 b (generally referred tousing reference numeral 130), and a cache memory 140 in communicationwith the central processing unit 101.

The central processing unit 101 is any logic circuitry that responds toand processes instructions fetched from the main memory unit 122. Inmany embodiments, the central processing unit is provided by amicroprocessor unit, such as: those manufactured by Intel Corporation ofMountain View, Calif.; those manufactured by Motorola Corporation ofSchaumburg, Ill.; those manufactured by Transmeta Corporation of SantaClara, Calif.; the RS/6000 processor, those manufactured byInternational Business Machines of White Plains, N.Y.; or thosemanufactured by Advanced Micro Devices of Sunnyvale, Calif. Thecomputing device 100 may be based on any of these processors, or anyother processor capable of operating as described herein.

Main memory unit 122 may be one or more memory chips capable of storingdata and allowing any storage location to be directly accessed by themicroprocessor 101, such as Static random access memory (SRAM), BurstSRAM or SynchBurst SRAM (BSRAM), Dynamic random access memory (DRAM),Fast Page Mode DRAM (FPM DRAM), Enhanced DRAM (EDRAM), Extended DataOutput RAM (EDO RAM), Extended Data Output DRAM (EDO DRAM), BurstExtended Data Output DRAM (BEDO DRAM), Enhanced DRAM (EDRAM),synchronous DRAM (SDRAM), JEDEC SRAM, PC100 SDRAM, Double Data RateSDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), SyncLink DRAM (SLDRAM),Direct Rambus DRAM (DRDRAM), or Ferroelectric RAM (FRAM). The mainmemory 122 may be based on any of the above described memory chips, orany other available memory chips capable of operating as describedherein. In the embodiment shown in FIG. 1E, the processor 101communicates with main memory 122 via a system bus 150 (described inmore detail below). FIG. 1E depicts an embodiment of a computing device100 in which the processor communicates directly with main memory 122via a memory port 103. For example, in FIG. 1F the main memory 122 maybe DRDRAM.

FIG. 1F depicts an embodiment in which the main processor 101communicates directly with cache memory 140 via a secondary bus,sometimes referred to as a backside bus. In other embodiments, the mainprocessor 101 communicates with cache memory 140 using the system bus150. Cache memory 140 typically has a faster response time than mainmemory 122 and is typically provided by SRAM, BSRAM, or EDRAM. In theembodiment shown in FIG. 1E, the processor 101 communicates with variousI/O devices 130 via a local system bus 150. Various busses may be usedto connect the central processing unit 101 to any of the I/O devices130, including a VESA VL bus, an ISA bus, an EISA bus, a MicroChannelArchitecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or aNuBus. For embodiments in which the I/O device is a video display 124,the processor 101 may use an Advanced Graphics Port (AGP) to communicatewith the display 124. FIG. 1F depicts an embodiment of a computer 100 inwhich the main processor 101 communicates directly with I/O device 130via HyperTransport, Rapid I/O, or InfiniBand. FIG. 1F also depicts anembodiment in which local busses and direct communication are mixed: theprocessor 101 communicates with I/O device 130 using a localinterconnect bus while communicating with I/O device 130 directly.

The computing device 100 may support any suitable installation device116, such as a floppy disk drive for receiving floppy disks such as3.5-inch, 5.25-inch disks or ZIP disks, a CD-ROM drive, a CD-R/RW drive,a DVD-ROM drive, tape drives of various formats, USB device, hard-driveor any other device suitable for installing software and programs suchas any client agent 120, or portion thereof. The computing device 100may further comprise a storage device 128, such as one or more hard diskdrives or redundant arrays of independent disks, for storing anoperating system and other related software, and for storing applicationsoftware programs such as any program related to the client agent 120.Optionally, any of the installation devices 116 could also be used asthe storage device 128. Additionally, the operating system and thesoftware can be run from a bootable medium, for example, a bootable CD,such as KNOPPIX®, a bootable CD for GNU/Linux that is available as aGNU/Linux distribution from knoppix.net.

Furthermore, the computing device 100 may include a network interface118 to interface to a Local Area Network (LAN), Wide Area Network (WAN)or the Internet through a variety of connections including, but notlimited to, standard telephone lines, LAN or WAN links (e.g., 802.11,T1, T3, 56 kb, X.25), broadband connections (e.g., ISDN, Frame Relay,ATM), wireless connections, or some combination of any or all of theabove. The network interface 118 may comprise a built-in networkadapter, network interface card, PCMCIA network card, card bus networkadapter, wireless network adapter, USB network adapter, modem or anyother device suitable for interfacing the computing device 100 to anytype of network capable of communication and performing the operationsdescribed herein. A wide variety of I/O devices 130 a-130 n may bepresent in the computing device 100. Input devices include keyboards,mice, trackpads, trackballs, microphones, and drawing tablets. Outputdevices include video displays, speakers, inkjet printers, laserprinters, and dye-sublimation printers. The I/O devices 130 may becontrolled by an I/O controller 123 as shown in FIG. 1E. The I/Ocontroller may control one or more I/O devices such as a keyboard 126and a pointing device 127, e.g., a mouse or optical pen. Furthermore, anI/O device may also provide storage 128 and/or an installation medium116 for the computing device 100. In still other embodiments, thecomputing device 100 may provide USB connections to receive handheld USBstorage devices such as the USB Flash Drive line of devices manufacturedby Twintech Industry, Inc. of Los Alamitos, Calif.

In some embodiments, the computing device 100 may comprise or beconnected to multiple display devices 124 a-124 n, which each may be ofthe same or different type and/or form. As such, any of the I/O devices130 a-130 n and/or the I/O controller 123 may comprise any type and/orform of suitable hardware, software, or combination of hardware andsoftware to support, enable or provide for the connection and use ofmultiple display devices 124 a-124 n by the computing device 100. Forexample, the computing device 100 may include any type and/or form ofvideo adapter, video card, driver, and/or library to interface,communicate, connect or otherwise use the display devices 124 a-124 n.In one embodiment, a video adapter may comprise multiple connectors tointerface to multiple display devices 124 a-124 n. In other embodiments,the computing device 100 may include multiple video adapters, with eachvideo adapter connected to one or more of the display devices 124 a-124n. In some embodiments, any portion of the operating system of thecomputing device 100 may be configured for using multiple displays 124a-124 n. In other embodiments, one or more of the display devices 124a-124 n may be provided by one or more other computing devices, such ascomputing devices 100 a and 100 b connected to the computing device 100,for example, via a network. These embodiments may include any type ofsoftware designed and constructed to use another computer's displaydevice as a second display device 124 a for the computing device 100.One ordinarily skilled in the art will recognize and appreciate thevarious ways and embodiments that a computing device 100 may beconfigured to have multiple display devices 124 a-124 n.

In further embodiments, an I/O device 130 may be a bridge 170 betweenthe system bus 150 and an external communication bus, such as a USB bus,an Apple Desktop Bus, an RS-232 serial connection, a SCSI bus, aFireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, aGigabit Ethernet bus, an Asynchronous Transfer Mode bus, a HIPPI bus, aSuper HIPPI bus, a SerialPlus bus, a SCI/LAMP bus, a FibreChannel bus,or a Serial Attached small computer system interface bus.

A computing device 100 of the sort depicted in FIGS. 1E and 1F typicallyoperate under the control of operating systems, which control schedulingof tasks and access to system resources. The computing device 100 can berunning any operating system such as any of the versions of theMicrosoft® Windows operating systems, the different releases of the Unixand Linux operating systems, any version of the Mac OS® for Macintoshcomputers, any embedded operating system, any real-time operatingsystem, any open source operating system, any proprietary operatingsystem, any operating systems for mobile computing devices, or any otheroperating system capable of running on the computing device andperforming the operations described herein. Typical operating systemsinclude: WINDOWS 3.x, WINDOWS 95, WINDOWS 98, WINDOWS 2000, WINDOWS NT3.51, WINDOWS NT 4.0, WINDOWS CE, and WINDOWS XP, all of which aremanufactured by Microsoft Corporation of Redmond, Wash.; MacOS,manufactured by Apple Computer of Cupertino, Calif.; OS/2, manufacturedby International Business Machines of Armonk, N.Y.; and Linux, afreely-available operating system distributed by Caldera Corp. of SaltLake City, Utah, or any type and/or form of a Unix operating system,among others.

In other embodiments, the computing device 100 may have differentprocessors, operating systems, and input devices consistent with thedevice. For example, in one embodiment the computer 100 is a Treo 180,270, 1060, 600 or 650 smart phone manufactured by Palm, Inc. In thisembodiment, the Treo smart phone is operated under the control of thePalmOS operating system and includes a stylus input device as well as afive-way navigator device. Moreover, the computing device 100 can be anyworkstation, desktop computer, laptop or notebook computer, server,handheld computer, mobile telephone, any other computer, or other formof computing or telecommunications device that is capable ofcommunication and that has sufficient processor power and memorycapacity to perform the operations described herein.

As shown in FIG. 1G, the computing device 100 may comprise multipleprocessors and may provide functionality for simultaneous execution ofinstructions or for simultaneous execution of one instruction on morethan one piece of data. In some embodiments, the computing device 100may comprise a parallel processor with one or more cores. In one ofthese embodiments, the computing device 100 is a shared memory paralleldevice, with multiple processors and/or multiple processor cores,accessing all available memory as a single global address space. Inanother of these embodiments, the computing device 100 is a distributedmemory parallel device with multiple processors each accessing localmemory only. In still another of these embodiments, the computing device100 has both some memory which is shared and some memory which can onlybe accessed by particular processors or subsets of processors. In stilleven another of these embodiments, the computing device 100, such as amulticore microprocessor, combines two or more independent processorsinto a single package, often a single integrated circuit (IC). In yetanother of these embodiments, the computing device 100 includes a chiphaving a CELL BROADBAND ENGINE architecture and including a Powerprocessor element and a plurality of synergistic processing elements,the Power processor element and the plurality of synergistic processingelements linked together by an internal high speed bus, which may bereferred to as an element interconnect bus.

In some embodiments, the processors provide functionality for executionof a single instruction simultaneously on multiple pieces of data(SIMD). In other embodiments, the processors provide functionality forexecution of multiple instructions simultaneously on multiple pieces ofdata (MIMD). In still other embodiments, the processor may use anycombination of SIMD and MIMD cores in a single device.

In some embodiments, the computing device 100 may comprise a graphicsprocessing unit. In one of these embodiments, depicted in FIG. 1H, thecomputing device 100 includes at least one central processing unit 101and at least one graphics processing unit. In another of theseembodiments, the computing device 100 includes at least one parallelprocessing unit and at least one graphics processing unit. In stillanother of these embodiments, the computing device 100 includes aplurality of processing units of any type, one of the plurality ofprocessing units comprising a graphics processing unit.

In some embodiments, a first computing device 100 a executes anapplication on behalf of a user of a client computing device 100 b. Inother embodiments, a computing device 100 a executes a virtual machine,which provides an execution session within which applications execute onbehalf of a user or a client computing devices 100 b. In one of theseembodiments, the execution session is a hosted desktop session. Inanother of these embodiments, the computing device 100 executes aterminal services session. The terminal services session may provide ahosted desktop environment. In still another of these embodiments, theexecution session provides access to a computing environment, which maycomprise one or more of: an application, a plurality of applications, adesktop application, and a desktop session in which one or moreapplications may execute.

B. Appliance Architecture

FIG. 2A illustrates an example embodiment of the appliance 200. Thearchitecture of the appliance 200 in FIG. 2A is provided by way ofillustration only and is not intended to be limiting. As shown in FIG.2A, appliance 200 comprises a hardware layer 206 and a software layerdivided into a user space 202 and a kernel space 204.

Hardware layer 206 provides the hardware elements upon which programsand services within kernel space 204 and user space 202 are executed.Hardware layer 206 also provides the structures and elements which allowprograms and services within kernel space 204 and user space 202 tocommunicate data both internally and externally with respect toappliance 200. As shown in FIG. 2A, the hardware layer 206 includes aprocessing unit 262 for executing software programs and services, amemory 264 for storing software and data, network ports 266 fortransmitting and receiving data over a network, and an encryptionprocessor 260 for performing functions related to Secure Sockets Layerprocessing of data transmitted and received over the network. In someembodiments, the central processing unit 262 may perform the functionsof the encryption processor 260 in a single processor. Additionally, thehardware layer 206 may comprise multiple processors for each of theprocessing unit 262 and the encryption processor 260. The processor 262may include any of the processors 101 described above in connection withFIGS. 1E and 1F. In some embodiments, the central processing unit 262may perform the functions of the encryption processor 260 in a singleprocessor. Additionally, the hardware layer 206 may comprise multipleprocessors for each of the processing unit 262 and the encryptionprocessor 260. For example, in one embodiment, the appliance 200comprises a first processor 262 and a second processor 262′. In otherembodiments, the processor 262 or 262′ comprises a multi-core processor.

Although the hardware layer 206 of appliance 200 is generallyillustrated with an encryption processor 260, processor 260 may be aprocessor for performing functions related to any encryption protocol,such as the Secure Socket Layer (SSL) or Transport Layer Security (TLS)protocol. In some embodiments, the processor 260 may be a generalpurpose processor (GPP), and in further embodiments, may be haveexecutable instructions for performing processing of any securityrelated protocol.

Although the hardware layer 206 of appliance 200 is illustrated withcertain elements in FIG. 2A, the hardware portions or components ofappliance 200 may comprise any type and form of elements, hardware orsoftware, of a computing device, such as the computing device 100illustrated and discussed herein in conjunction with FIGS. 1E and 1F. Insome embodiments, the appliance 200 may comprise a server, gateway,router, switch, bridge or other type of computing or network device, andhave any hardware and/or software elements associated therewith.

The operating system of appliance 200 allocates, manages, or otherwisesegregates the available system memory into kernel space 204 and userspace 204. In example software architecture 200, the operating systemmay be any type and/or form of Unix operating system although theinvention is not so limited. As such, the appliance 200 can be runningany operating system such as any of the versions of the Microsoft®Windows operating systems, the different releases of the Unix and Linuxoperating systems, any version of the Mac OS® for Macintosh computers,any embedded operating system, any network operating system, anyreal-time operating system, any open source operating system, anyproprietary operating system, any operating systems for mobile computingdevices or network devices, or any other operating system capable ofrunning on the appliance 200 and performing the operations describedherein.

The kernel space 204 is reserved for running the kernel 230, includingany device drivers, kernel extensions or other kernel related software.As known to those skilled in the art, the kernel 230 is the core of theoperating system, and provides access, control, and management ofresources and hardware-related elements of the application 104. Inaccordance with an embodiment of the appliance 200, the kernel space 204also includes a number of network services or processes working inconjunction with a cache manager 232, sometimes also referred to as theintegrated cache, the benefits of which are described in detail furtherherein. Additionally, the embodiment of the kernel 230 will depend onthe embodiment of the operating system installed, configured, orotherwise used by the device 200.

In one embodiment, the device 200 comprises one network stack 267, suchas a TCP/IP based stack, for communicating with the client 102 and/orthe server 106. In one embodiment, the network stack 267 is used tocommunicate with a first network, such as network 108, and a secondnetwork 110. In some embodiments, the device 200 terminates a firsttransport layer connection, such as a TCP connection of a client 102,and establishes a second transport layer connection to a server 106 foruse by the client 102, e.g., the second transport layer connection isterminated at the appliance 200 and the server 106. The first and secondtransport layer connections may be established via a single networkstack 267. In other embodiments, the device 200 may comprise multiplenetwork stacks, for example 267 and 267′, and the first transport layerconnection may be established or terminated at one network stack 267,and the second transport layer connection on the second network stack267′. For example, one network stack may be for receiving andtransmitting network packet on a first network, and another networkstack for receiving and transmitting network packets on a secondnetwork. In one embodiment, the network stack 267 comprises a buffer 243for queuing one or more network packets for transmission by theappliance 200.

As shown in FIG. 2, the kernel space 204 includes the cache manager 232,a high-speed layer 2-7 integrated packet engine 240, an encryptionengine 234, a policy engine 236 and multi-protocol compression logic238. Running these components or processes 232, 240, 234, 236 and 238 inkernel space 204 or kernel mode instead of the user space 202 improvesthe performance of each of these components, alone and in combination.Kernel operation means that these components or processes 232, 240, 234,236 and 238 run in the core address space of the operating system of thedevice 200. For example, running the encryption engine 234 in kernelmode improves encryption performance by moving encryption and decryptionoperations to the kernel, thereby reducing the number of transitionsbetween the memory space or a kernel thread in kernel mode and thememory space or a thread in user mode. For example, data obtained inkernel mode may not need to be passed or copied to a process or threadrunning in user mode, such as from a kernel level data structure to auser level data structure. In another aspect, the number of contextswitches between kernel mode and user mode are also reduced.Additionally, synchronization of and communications between any of thecomponents or processes 232, 240, 235, 236 and 238 can be performed moreefficiently in the kernel space 204.

In some embodiments, any portion of the components 232, 240, 234, 236and 238 may run or operate in the kernel space 204, while other portionsof these components 232, 240, 234, 236 and 238 may run or operate inuser space 202. In one embodiment, the appliance 200 uses a kernel-leveldata structure providing access to any portion of one or more networkpackets, for example, a network packet comprising a request from aclient 102 or a response from a server 106. In some embodiments, thekernel-level data structure may be obtained by the packet engine 240 viaa transport layer driver interface or filter to the network stack 267.The kernel-level data structure may comprise any interface and/or dataaccessible via the kernel space 204 related to the network stack 267,network traffic or packets received or transmitted by the network stack267. In other embodiments, the kernel-level data structure may be usedby any of the components or processes 232, 240, 234, 236 and 238 toperform the desired operation of the component or process. In oneembodiment, a component 232, 240, 234, 236 and 238 is running in kernelmode 204 when using the kernel-level data structure, while in anotherembodiment, the component 232, 240, 234, 236 and 238 is running in usermode when using the kernel-level data structure. In some embodiments,the kernel-level data structure may be copied or passed to a secondkernel-level data structure, or any desired user-level data structure.

The cache manager 232 may comprise software, hardware or any combinationof software and hardware to provide cache access, control and managementof any type and form of content, such as objects or dynamicallygenerated objects served by the originating servers 106. The data,objects or content processed and stored by the cache manager 232 maycomprise data in any format, such as a markup language, or communicatedvia any protocol. In some embodiments, the cache manager 232 duplicatesoriginal data stored elsewhere or data previously computed, generated ortransmitted, in which the original data may require longer access timeto fetch, compute or otherwise obtain relative to reading a cache memoryelement. Once the data is stored in the cache memory element, future usecan be made by accessing the cached copy rather than refetching orrecomputing the original data, thereby reducing the access time. In someembodiments, the cache memory element may comprise a data object inmemory 264 of device 200. In other embodiments, the cache memory elementmay comprise memory having a faster access time than memory 264. Inanother embodiment, the cache memory element may comprise any type andform of storage element of the device 200, such as a portion of a harddisk. In some embodiments, the processing unit 262 may provide cachememory for use by the cache manager 232. In yet further embodiments, thecache manager 232 may use any portion and combination of memory,storage, or the processing unit for caching data, objects, and othercontent.

Furthermore, the cache manager 232 includes any logic, functions, rules,or operations to perform any embodiments of the techniques of theappliance 200 described herein. For example, the cache manager 232includes logic or functionality to invalidate objects based on theexpiration of an invalidation time period or upon receipt of aninvalidation command from a client 102 or server 106. In someembodiments, the cache manager 232 may operate as a program, service,process or task executing in the kernel space 204, and in otherembodiments, in the user space 202. In one embodiment, a first portionof the cache manager 232 executes in the user space 202 while a secondportion executes in the kernel space 204. In some embodiments, the cachemanager 232 can comprise any type of general purpose processor (GPP), orany other type of integrated circuit, such as a Field Programmable GateArray (FPGA), Programmable Logic Device (PLD), or Application SpecificIntegrated Circuit (ASIC).

The policy engine 236 may include, for example, an intelligentstatistical engine or other programmable application(s). In oneembodiment, the policy engine 236 provides a configuration mechanism toallow a user to identifying, specify, define or configure a cachingpolicy. Policy engine 236, in some embodiments, also has access tomemory to support data structures such as lookup tables or hash tablesto enable user-selected caching policy decisions. In other embodiments,the policy engine 236 may comprise any logic, rules, functions oroperations to determine and provide access, control and management ofobjects, data or content being cached by the appliance 200 in additionto access, control and management of security, network traffic, networkaccess, compression or any other function or operation performed by theappliance 200. Further examples of specific caching policies are furtherdescribed herein.

The encryption engine 234 comprises any logic, business rules, functionsor operations for handling the processing of any security relatedprotocol, such as SSL or TLS, or any function related thereto. Forexample, the encryption engine 234 encrypts and decrypts networkpackets, or any portion thereof, communicated via the appliance 200. Theencryption engine 234 may also setup or establish SSL or TLS connectionson behalf of the client 102 a-102 n, server 106 a-106 n, or appliance200. As such, the encryption engine 234 provides offloading andacceleration of SSL processing. In one embodiment, the encryption engine234 uses a tunneling protocol to provide a virtual private networkbetween a client 102 a-102 n and a server 106 a-106 n. In someembodiments, the encryption engine 234 is in communication with theEncryption processor 260. In other embodiments, the encryption engine234 comprises executable instructions running on the Encryptionprocessor 260.

The multi-protocol compression engine 238 comprises any logic, businessrules, function or operations for compressing one or more protocols of anetwork packet, such as any of the protocols used by the network stack267 of the device 200. In one embodiment, multi-protocol compressionengine 238 compresses bi-directionally between clients 102 a-102 n andservers 106 a-106 n any TCP/IP based protocol, including MessagingApplication Programming Interface (MAPI) (email), File Transfer Protocol(FTP), HyperText Transfer Protocol (HTTP), Common Internet File System(CIFS) protocol (file transfer), Independent Computing Architecture(ICA) protocol, Remote Desktop Protocol (RDP), Wireless ApplicationProtocol (WAP), Mobile IP protocol, and Voice Over IP (VoIP) protocol.In other embodiments, multi-protocol compression engine 238 providescompression of Hypertext Markup Language (HTML) based protocols and insome embodiments, provides compression of any markup languages, such asthe Extensible Markup Language (XML). In one embodiment, themulti-protocol compression engine 238 provides compression of anyhigh-performance protocol, such as any protocol designed for appliance200 to appliance 200 communications. In another embodiment, themulti-protocol compression engine 238 compresses any payload of or anycommunication using a modified transport control protocol, such asTransaction TCP (T/TCP), TCP with selection acknowledgements (TCP-SACK),TCP with large windows (TCP-LW), a congestion prediction protocol suchas the TCP-Vegas protocol, and a TCP spoofing protocol.

As such, the multi-protocol compression engine 238 acceleratesperformance for users accessing applications via desktop clients, e.g.,Microsoft Outlook and non-Web thin clients, such as any client launchedby popular enterprise applications like Oracle, SAP and Siebel, and evenmobile clients, such as the Pocket PC. In some embodiments, themulti-protocol compression engine 238 by executing in the kernel mode204 and integrating with packet processing engine 240 accessing thenetwork stack 267 is able to compress any of the protocols carried bythe TCP/IP protocol, such as any application layer protocol.

High speed layer 2-7 integrated packet engine 240, also generallyreferred to as a packet processing engine or packet engine, isresponsible for managing the kernel-level processing of packets receivedand transmitted by appliance 200 via network ports 266. The high speedlayer 2-7 integrated packet engine 240 may comprise a buffer for queuingone or more network packets during processing, such as for receipt of anetwork packet or transmission of a network packer. Additionally, thehigh speed layer 2-7 integrated packet engine 240 is in communicationwith one or more network stacks 267 to send and receive network packetsvia network ports 266. The high speed layer 2-7 integrated packet engine240 works in conjunction with encryption engine 234, cache manager 232,policy engine 236 and multi-protocol compression logic 238. Inparticular, encryption engine 234 is configured to perform SSLprocessing of packets, policy engine 236 is configured to performfunctions related to traffic management such as request-level contentswitching and request-level cache redirection, and multi-protocolcompression logic 238 is configured to perform functions related tocompression and decompression of data.

The high speed layer 2-7 integrated packet engine 240 includes a packetprocessing timer 242. In one embodiment, the packet processing timer 242provides one or more time intervals to trigger the processing ofincoming, i.e., received, or outgoing, i.e., transmitted, networkpackets. In some embodiments, the high speed layer 2-7 integrated packetengine 240 processes network packets responsive to the timer 242. Thepacket processing timer 242 provides any type and form of signal to thepacket engine 240 to notify, trigger, or communicate a time relatedevent, interval or occurrence. In many embodiments, the packetprocessing timer 242 operates in the order of milliseconds, such as forexample 100 ms, 50 ms or 25 ms. For example, in some embodiments, thepacket processing timer 242 provides time intervals or otherwise causesa network packet to be processed by the high speed layer 2-7 integratedpacket engine 240 at a 10 ms time interval, while in other embodiments,at a 5 ms time interval, and still yet in further embodiments, as shortas a 3, 2, or 1 ms time interval. The high speed layer 2-7 integratedpacket engine 240 may be interfaced, integrated or in communication withthe encryption engine 234, cache manager 232, policy engine 236 andmulti-protocol compression engine 238 during operation. As such, any ofthe logic, functions, or operations of the encryption engine 234, cachemanager 232, policy engine 236 and multi-protocol compression logic 238may be performed responsive to the packet processing timer 242 and/orthe packet engine 240. Therefore, any of the logic, functions, oroperations of the encryption engine 234, cache manager 232, policyengine 236 and multi-protocol compression logic 238 may be performed atthe granularity of time intervals provided via the packet processingtimer 242, for example, at a time interval of less than or equal to 10ms. For example, in one embodiment, the cache manager 232 may performinvalidation of any cached objects responsive to the high speed layer2-7 integrated packet engine 240 and/or the packet processing timer 242.In another embodiment, the expiry or invalidation time of a cachedobject can be set to the same order of granularity as the time intervalof the packet processing timer 242, such as at every 10 ms.

In contrast to kernel space 204, user space 202 is the memory area orportion of the operating system used by user mode applications orprograms otherwise running in user mode. A user mode application may notaccess kernel space 204 directly and uses service calls in order toaccess kernel services. As shown in FIG. 2, user space 202 of appliance200 includes a graphical user interface (GUI) 210, a command lineinterface (CLI) 212, shell services 214, health monitoring program 216,and daemon services 218. GUI 210 and CLI 212 provide a means by which asystem administrator or other user can interact with and control theoperation of appliance 200, such as via the operating system of theappliance 200 and either is user space 202 or kernel space 204. The GUI210 may be any type and form of graphical user interface and may bepresented via text, graphical or otherwise, by any type of program orapplication, such as a browser. The CLI 212 may be any type and form ofcommand line or text-based interface, such as a command line provided bythe operating system. For example, the CLI 212 may comprise a shell,which is a tool to enable users to interact with the operating system.In some embodiments, the CLI 212 may be provided via a bash, csh, tcsh,or ksh type shell. The shell services 214 comprises the programs,services, tasks, processes or executable instructions to supportinteraction with the appliance 200 or operating system by a user via theGUI 210 and/or CLI 212.

Health monitoring program 216 is used to monitor, check, report andensure that network systems are functioning properly and that users arereceiving requested content over a network. Health monitoring program216 comprises one or more programs, services, tasks, processes orexecutable instructions to provide logic, rules, functions or operationsfor monitoring any activity of the appliance 200. In some embodiments,the health monitoring program 216 intercepts and inspects any networktraffic passed via the appliance 200. In other embodiments, the healthmonitoring program 216 interfaces by any suitable means and/ormechanisms with one or more of the following: the encryption engine 234,cache manager 232, policy engine 236, multi-protocol compression logic238, packet engine 240, daemon services 218, and shell services 214. Assuch, the health monitoring program 216 may call any applicationprogramming interface (API) to determine a state, status, or health ofany portion of the appliance 200. For example, the health monitoringprogram 216 may ping or send a status inquiry on a periodic basis tocheck if a program, process, service or task is active and currentlyrunning. In another example, the health monitoring program 216 may checkany status, error or history logs provided by any program, process,service or task to determine any condition, status or error with anyportion of the appliance 200.

Daemon services 218 are programs that run continuously or in thebackground and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests toother programs or processes, such as another daemon service 218 asappropriate. As known to those skilled in the art, a daemon service 218may run unattended to perform continuous or periodic system widefunctions, such as network control, or to perform any desired task. Insome embodiments, one or more daemon services 218 run in the user space202, while in other embodiments, one or more daemon services 218 run inthe kernel space.

Referring now to FIG. 2B, another embodiment of the appliance 200 isdepicted. In brief overview, the appliance 200 provides one or more ofthe following services, functionality or operations: SSL VPNconnectivity 280, switching/load balancing 284, Domain Name Serviceresolution 286, acceleration 288 and an application firewall 290 forcommunications between one or more clients 102 and one or more servers106. Each of the servers 106 may provide one or more network relatedservices 270 a-270 n (referred to as services 270). For example, aserver 106 may provide an http service 270. The appliance 200 comprisesone or more virtual servers or virtual internet protocol servers,referred to as a vServer, VIP server, or just VIP 275 a-275 n (alsoreferred herein as vServer 275). The vServer 275 receives, intercepts orotherwise processes communications between a client 102 and a server 106in accordance with the configuration and operations of the appliance200.

The vServer 275 may comprise software, hardware or any combination ofsoftware and hardware. The vServer 275 may comprise any type and form ofprogram, service, task, process or executable instructions operating inuser mode 202, kernel mode 204 or any combination thereof in theappliance 200. The vServer 275 includes any logic, functions, rules, oroperations to perform any embodiments of the techniques describedherein, such as SSL VPN 280, switching/load balancing 284, Domain NameService resolution 286, acceleration 288 and an application firewall290. In some embodiments, the vServer 275 establishes a connection to aservice 270 of a server 106. The service 270 may comprise any program,application, process, task or set of executable instructions capable ofconnecting to and communicating to the appliance 200, client 102 orvServer 275. For example, the service 270 may comprise a web server,http server, ftp, email or database server. In some embodiments, theservice 270 is a daemon process or network driver for listening,receiving and/or sending communications for an application, such asemail, database or an enterprise application. In some embodiments, theservice 270 may communicate on a specific IP address, or IP address andport.

In some embodiments, the vServer 275 applies one or more policies of thepolicy engine 236 to network communications between the client 102 andserver 106. In one embodiment, the policies are associated with aVServer 275. In another embodiment, the policies are based on a user, ora group of users. In yet another embodiment, a policy is global andapplies to one or more vServers 275 a-275 n, and any user or group ofusers communicating via the appliance 200. In some embodiments, thepolicies of the policy engine have conditions upon which the policy isapplied based on any content of the communication, such as internetprotocol address, port, protocol type, header or fields in a packet, orthe context of the communication, such as user, group of the user,vServer 275, transport layer connection, and/or identification orattributes of the client 102 or server 106.

In other embodiments, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to access the computingenvironment 15, application, and/or data file from a server 106. Inanother embodiment, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to have the application deliverysystem 190 deliver one or more of the computing environment 15,application, and/or data file. In yet another embodiment, the appliance200 establishes a VPN or SSL VPN connection based on the policy engine's236 authentication and/or authorization of a remote user or a remoteclient 103 In one embodiment, the appliance 102 controls the flow ofnetwork traffic and communication sessions based on policies of thepolicy engine 236. For example, the appliance 200 may control the accessto a computing environment 15, application or data file based on thepolicy engine 236.

In some embodiments, the vServer 275 establishes a transport layerconnection, such as a TCP or UDP connection with a client 102 via theclient agent 120. In one embodiment, the vServer 275 listens for andreceives communications from the client 102. In other embodiments, thevServer 275 establishes a transport layer connection, such as a TCP orUDP connection with a client server 106. In one embodiment, the vServer275 establishes the transport layer connection to an internet protocoladdress and port of a server 270 running on the server 106. In anotherembodiment, the vServer 275 associates a first transport layerconnection to a client 102 with a second transport layer connection tothe server 106. In some embodiments, a vServer 275 establishes a pool oftransport layer connections to a server 106 and multiplexes clientrequests via the pooled transport layer connections.

In some embodiments, the appliance 200 provides a SSL VPN connection 280between a client 102 and a server 106. For example, a client 102 on afirst network 102 requests to establish a connection to a server 106 ona second network 104′. In some embodiments, the second network 104′ isnot routable from the first network 104. In other embodiments, theclient 102 is on a public network 104 and the server 106 is on a privatenetwork 104′, such as a corporate network. In one embodiment, the clientagent 120 intercepts communications of the client 102 on the firstnetwork 104, encrypts the communications, and transmits thecommunications via a first transport layer connection to the appliance200. The appliance 200 associates the first transport layer connectionon the first network 104 to a second transport layer connection to theserver 106 on the second network 104. The appliance 200 receives theintercepted communication from the client agent 102, decrypts thecommunications, and transmits the communication to the server 106 on thesecond network 104 via the second transport layer connection. The secondtransport layer connection may be a pooled transport layer connection.As such, the appliance 200 provides an end-to-end secure transport layerconnection for the client 102 between the two networks 104, 104′.

In one embodiment, the appliance 200 hosts an intranet internet protocolor intranetIP 282 address of the client 102 on the virtual privatenetwork 104. The client 102 has a local network identifier, such as aninternet protocol (IP) address and/or host name on the first network104. When connected to the second network 104′ via the appliance 200,the appliance 200 establishes, assigns or otherwise provides anIntranetIP, which is network identifier, such as IP address and/or hostname, for the client 102 on the second network 104′. The appliance 200listens for and receives on the second or private network 104′ for anycommunications directed towards the client 102 using the client'sestablished IntranetIP 282. In one embodiment, the appliance 200 acts asor on behalf of the client 102 on the second private network 104. Forexample, in another embodiment, a vServer 275 listens for and respondsto communications to the IntranetIP 282 of the client 102. In someembodiments, if a computing device 100 on the second network 104′transmits a request, the appliance 200 processes the request as if itwere the client 102. For example, the appliance 200 may respond to aping to the client's IntranetIP 282. In another example, the appliancemay establish a connection, such as a TCP or UDP connection, withcomputing device 100 on the second network 104 requesting a connectionwith the client's IntranetIP 282.

In some embodiments, the appliance 200 provides one or more of thefollowing acceleration techniques 288 to communications between theclient 102 and server 106: 1) compression; 2) decompression; 3)Transmission Control Protocol pooling; 4) Transmission Control Protocolmultiplexing; 5) Transmission Control Protocol buffering; and 6)caching. In one embodiment, the appliance 200 relieves servers 106 ofmuch of the processing load caused by repeatedly opening and closingtransport layers connections to clients 102 by opening one or moretransport layer connections with each server 106 and maintaining theseconnections to allow repeated data accesses by clients via the Internet.This technique is referred to herein as “connection pooling”.

In some embodiments, in order to seamlessly splice communications from aclient 102 to a server 106 via a pooled transport layer connection, theappliance 200 translates or multiplexes communications by modifyingsequence number and acknowledgment numbers at the transport layerprotocol level. This is referred to as “connection multiplexing”. Insome embodiments, no application layer protocol interaction is required.For example, in the case of an in-bound packet (that is, a packetreceived from a client 102), the source network address of the packet ischanged to that of an output port of appliance 200, and the destinationnetwork address is changed to that of the intended server. In the caseof an outbound packet (that is, one received from a server 106), thesource network address is changed from that of the server 106 to that ofan output port of appliance 200 and the destination address is changedfrom that of appliance 200 to that of the requesting client 102. Thesequence numbers and acknowledgment numbers of the packet are alsotranslated to sequence numbers and acknowledgement expected by theclient 102 on the appliance's 200 transport layer connection to theclient 102. In some embodiments, the packet checksum of the transportlayer protocol is recalculated to account for these translations.

In another embodiment, the appliance 200 provides switching orload-balancing functionality 284 for communications between the client102 and server 106. In some embodiments, the appliance 200 distributestraffic and directs client requests to a server 106 based on layer 4 orapplication-layer request data. In one embodiment, although the networklayer or layer 2 of the network packet identifies a destination server106, the appliance 200 determines the server 106 to distribute thenetwork packet by application information and data carried as payload ofthe transport layer packet. In one embodiment, the health monitoringprograms 216 of the appliance 200 monitor the health of servers todetermine the server 106 for which to distribute a client's request. Insome embodiments, if the appliance 200 detects a server 106 is notavailable or has a load over a predetermined threshold, the appliance200 can direct or distribute client requests to another server 106.

In some embodiments, the appliance 200 acts as a Domain Name Service(DNS) resolver or otherwise provides resolution of a DNS request fromclients 102. In some embodiments, the appliance intercepts' a DNSrequest transmitted by the client 102. In one embodiment, the appliance200 responds to a client's DNS request with an IP address of or hostedby the appliance 200. In this embodiment, the client 102 transmitsnetwork communication for the domain name to the appliance 200. Inanother embodiment, the appliance 200 responds to a client's DNS requestwith an IP address of or hosted by a second appliance 200′. In someembodiments, the appliance 200 responds to a client's DNS request withan IP address of a server 106 determined by the appliance 200.

In yet another embodiment, the appliance 200 provides applicationfirewall functionality 290 for communications between the client 102 andserver 106. In one embodiment, the policy engine 236 provides rules fordetecting and blocking illegitimate requests. In some embodiments, theapplication firewall 290 protects against denial of service (DoS)attacks. In other embodiments, the appliance inspects the content ofintercepted requests to identify and block application-based attacks. Insome embodiments, the rules/policy engine 236 comprises one or moreapplication firewall or security control policies for providingprotections against various classes and types of web or Internet basedvulnerabilities, such as one or more of the following: 1) bufferoverflow, 2) CGI-BIN parameter manipulation, 3) form/hidden fieldmanipulation, 4) forceful browsing, 5) cookie or session poisoning, 6)broken access control list (ACLs) or weak passwords, 7) cross-sitescripting (XSS), 8) command injection, 9) SQL injection, 10) errortriggering sensitive information leak, 11) insecure use of cryptography,12) server misconfiguration, 13) back doors and debug options, 14)website defacement, 15) platform or operating systems vulnerabilities,and 16) zero-day exploits. In an embodiment, the application firewall290 provides HTML form field protection in the form of inspecting oranalyzing the network communication for one or more of the following: 1)required fields are returned, 2) no added field allowed, 3) read-onlyand hidden field enforcement, 4) drop-down list and radio button fieldconformance, and 5) form-field max-length enforcement. In someembodiments, the application firewall 290 ensures cookies are notmodified. In other embodiments, the application firewall 290 protectsagainst forceful browsing by enforcing legal URLs.

In still yet other embodiments, the application firewall 290 protectsany confidential information contained in the network communication. Theapplication firewall 290 may inspect or analyze any networkcommunication in accordance with the rules or polices of the engine 236to identify any confidential information in any field of the networkpacket. In some embodiments, the application firewall 290 identifies inthe network communication one or more occurrences of a credit cardnumber, password, social security number, name, patient code, contactinformation, and age. The encoded portion of the network communicationmay comprise these occurrences or the confidential information. Based onthese occurrences, in one embodiment, the application firewall 290 maytake a policy action on the network communication, such as preventtransmission of the network communication. In another embodiment, theapplication firewall 290 may rewrite, remove or otherwise mask suchidentified occurrence or confidential information.

Still referring to FIG. 2B, the appliance 200 may include a performancemonitoring agent 197 as discussed above in conjunction with FIG. 1D. Inone embodiment, the appliance 200 receives the monitoring agent 197 fromthe monitoring service 1908 or monitoring server 106 as depicted in FIG.1D. In some embodiments, the appliance 200 stores the monitoring agent197 in storage, such as disk, for delivery to any client or server incommunication with the appliance 200. For example, in one embodiment,the appliance 200 transmits the monitoring agent 197 to a client uponreceiving a request to establish a transport layer connection. In otherembodiments, the appliance 200 transmits the monitoring agent 197 uponestablishing the transport layer connection with the client 102. Inanother embodiment, the appliance 200 transmits the monitoring agent 197to the client upon intercepting or detecting a request for a web page.In yet another embodiment, the appliance 200 transmits the monitoringagent 197 to a client or a server in response to a request from themonitoring server 198. In one embodiment, the appliance 200 transmitsthe monitoring agent 197 to a second appliance 200′ or appliance 205.

In other embodiments, the appliance 200 executes the monitoring agent197. In one embodiment, the monitoring agent 197 measures and monitorsthe performance of any application, program, process, service, task orthread executing on the appliance 200. For example, the monitoring agent197 may monitor and measure performance and operation of vServers275A-275N. In another embodiment, the monitoring agent 197 measures andmonitors the performance of any transport layer connections of theappliance 200. In some embodiments, the monitoring agent 197 measuresand monitors the performance of any user sessions traversing theappliance 200. In one embodiment, the monitoring agent 197 measures andmonitors the performance of any virtual private network connectionsand/or sessions traversing the appliance 200, such an SSL VPN session.In still further embodiments, the monitoring agent 197 measures andmonitors the memory, CPU and disk usage and performance of the appliance200. In yet another embodiment, the monitoring agent 197 measures andmonitors the performance of any acceleration technique 288 performed bythe appliance 200, such as SSL offloading, connection pooling andmultiplexing, caching, and compression. In some embodiments, themonitoring agent 197 measures and monitors the performance of any loadbalancing and/or content switching 284 performed by the appliance 200.In other embodiments, the monitoring agent 197 measures and monitors theperformance of application firewall 290 protection and processingperformed by the appliance 200.

C. Systems and Methods for Providing Virtual Appliance

Referring now to FIG. 3A, a block diagram depicts one embodiment of avirtualization environment 300. In brief overview, a computing device100 includes a hypervisor layer, a virtualization layer, and a hardwarelayer. The hypervisor layer includes a hypervisor 301 (also referred toas a virtualization manager) that allocates and manages access to anumber of physical resources in the hardware layer (e.g., theprocessor(s) 321, and disk(s) 328) by at least one virtual machineexecuting in the virtualization layer. The virtualization layer includesat least one operating system 310 and a plurality of virtual resourcesallocated to the at least one operating system 310. Virtual resourcesmay include, without limitation, a plurality of virtual processors 332a, 332 b, 332 c (generally 332), and virtual disks 342 a, 342 b, 342 c(generally 342), as well as virtual resources such as virtual memory andvirtual network interfaces. The plurality of virtual resources and theoperating system 310 may be referred to as a virtual machine 306. Avirtual machine 306 may include a control operating system 105 incommunication with the hypervisor 301 and used to execute applicationsfor managing and configuring other virtual machines on the computingdevice 100.

In greater detail, a hypervisor 301 may provide virtual resources to anoperating system in any manner which simulates the operating systemhaving access to a physical device. A hypervisor 301 may provide virtualresources to any number of guest operating systems 310 a, 310 b(generally 310). In some embodiments, a computing device 100 executesone or more types of hypervisors. In these embodiments, hypervisors maybe used to emulate virtual hardware, partition physical hardware,virtualize physical hardware, and execute virtual machines that provideaccess to computing environments. Hypervisors may include thosemanufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor,an open source product whose development is overseen by the open sourceXen.org community; HyperV, VirtualServer or virtual PC hypervisorsprovided by Microsoft, or others. In some embodiments, a computingdevice 100 executing a hypervisor that creates a virtual machineplatform on which guest operating systems may execute is referred to asa host server. In one of these embodiments, for example, the computingdevice 100 is a XEN SERVER provided by Citrix Systems, Inc., of FortLauderdale, Fla.

In some embodiments, a hypervisor 301 executes within an operatingsystem executing on a computing device. In one of these embodiments, acomputing device executing an operating system and a hypervisor 301 maybe said to have a host operating system (the operating system executingon the computing device), and a guest operating system (an operatingsystem executing within a computing resource partition provided by thehypervisor 301). In other embodiments, a hypervisor 301 interactsdirectly with hardware on a computing device, instead of executing on ahost operating system. In one of these embodiments, the hypervisor 301may be said to be executing on “bare metal,” referring to the hardwarecomprising the computing device.

In some embodiments, a hypervisor 301 may create a virtual machine 306a-c (generally 306) in which an operating system 310 executes. In one ofthese embodiments, for example, the hypervisor 301 loads a virtualmachine image to create a virtual machine 306. In another of theseembodiments, the hypervisor 301 executes an operating system 310 withinthe virtual machine 306. In still another of these embodiments, thevirtual machine 306 executes an operating system 310.

In some embodiments, the hypervisor 301 controls processor schedulingand memory partitioning for a virtual machine 306 executing on thecomputing device 100. In one of these embodiments, the hypervisor 301controls the execution of at least one virtual machine 106. In anotherof these embodiments, the hypervisor 301 presents at least one virtualmachine 306 with an abstraction of at least one hardware resourceprovided by the computing device 100. In other embodiments, thehypervisor 301 controls whether and how physical processor capabilitiesare presented to the virtual machine 306.

A control operating system 305 may execute at least one application formanaging and configuring the guest operating systems. In one embodiment,the control operating system 305 may execute an administrativeapplication, such as an application including a user interface providingadministrators with access to functionality for managing the executionof a virtual machine, including functionality for executing a virtualmachine, terminating an execution of a virtual machine, or identifying atype of physical resource for allocation to the virtual machine. Inanother embodiment, the hypervisor 301 executes the control operatingsystem 305 within a virtual machine 306 created by the hypervisor 301.In still another embodiment, the control operating system 305 executesin a virtual machine 306 that is authorized to directly access physicalresources on the computing device 100. In some embodiments, a controloperating system 305 a on a computing device 100 a may exchange datawith a control operating system 305 b on a computing device 100 b, viacommunications between a hypervisor 301 a and a hypervisor 301 b. Inthis way, one or more computing devices 100 may exchange data with oneor more of the other computing devices 100 regarding processors andother physical resources available in a pool of resources. In one ofthese embodiments, this functionality allows a hypervisor to manage apool of resources distributed across a plurality of physical computingdevices. In another of these embodiments, multiple hypervisors manageone or more of the guest operating systems executed on one of thecomputing devices 100.

In one embodiment, the control operating system 305 executes in avirtual machine 306 that is authorized to interact with at least oneguest operating system 310. In another embodiment, a guest operatingsystem 310 communicates with the control operating system 305 via thehypervisor 301 in order to request access to a disk or a network. Instill another embodiment, the guest operating system 310 and the controloperating system 305 may communicate via a communication channelestablished by the hypervisor 301, such as, for example, via a pluralityof shared memory pages made available by the hypervisor 301.

In some embodiments, the control operating system 105 includes a networkback-end driver for communicating directly with networking hardwareprovided by the computing device 100. In one of these embodiments, thenetwork back-end driver processes at least one virtual machine requestfrom at least one guest operating system 110. In other embodiments, thecontrol operating system 305 includes a block back-end driver forcommunicating with a storage element on the computing device 100. In oneof these embodiments, the block back-end driver reads and writes datafrom the storage element based upon at least one request received from aguest operating system 310.

In one embodiment, the control operating system 305 includes a toolsstack 304. In another embodiment, a tools stack 304 providesfunctionality for interacting with the hypervisor 301, communicatingwith other control operating systems 305 (for example, on a secondcomputing device 100 b), or managing virtual machines 306 b, 306 c onthe computing device 100. In another embodiment, the tools stack 304includes customized applications for providing improved managementfunctionality to an administrator of a virtual machine farm. In someembodiments, at least one of the tools stack 304 and the controloperating system 305 include a management API that provides an interfacefor remotely configuring and controlling virtual machines 306 running ona computing device 100. In other embodiments, the control operatingsystem 305 communicates with the hypervisor 301 through the tools stack104.

In one embodiment, the hypervisor 301 executes a guest operating system310 within a virtual machine 306 created by the hypervisor 301. Inanother embodiment, the guest operating system 310 provides a user ofthe computing device 100 with access to resources within a computingenvironment. In still another embodiment, a resource includes a program,an application, a document, a file, a plurality of applications, aplurality of files, an executable program file, a desktop environment, acomputing environment, or other resource made available to a user of thecomputing device 100. In yet another embodiment, the resource may bedelivered to the computing device 100 via a plurality of access methodsincluding, but not limited to, conventional installation directly on thecomputing device 100, delivery to the computing device 100 via a methodfor application streaming, delivery to the computing device 100 ofoutput data generated by an execution of the resource on a secondcomputing device 100′ and communicated to the computing device 100 via apresentation layer protocol, delivery to the computing device 100 ofoutput data generated by an execution of the resource via a virtualmachine executing on a second computing device 100′, or execution from aremovable storage device connected to the computing device 100, such asa USB device, or via a virtual machine executing on the computing device100 and generating output data. In some embodiments, the computingdevice 100 transmits output data generated by the execution of theresource to another computing device 100′.

In one embodiment, the guest operating system 310, in conjunction withthe virtual machine on which it executes, forms a fully-virtualizedvirtual machine which is not aware that it is a virtual machine; such amachine may be referred to as a “Domain U HVM (Hardware Virtual Machine)virtual machine”. In another embodiment, a fully-virtualized machineincludes software emulating a Basic Input/Output System (BIOS) in orderto execute an operating system within the fully-virtualized machine. Instill another embodiment, a fully-virtualized machine may include adriver that provides functionality by communicating with the hypervisor301. In such an embodiment, the driver may be aware that it executeswithin a virtualized environment. In another embodiment, the guestoperating system 310, in conjunction with the virtual machine on whichit executes, forms a paravirtualized virtual machine, which is awarethat it is a virtual machine; such a machine may be referred to as a“Domain U PV virtual machine”. In another embodiment, a paravirtualizedmachine includes additional drivers that a fully-virtualized machinedoes not include. In still another embodiment, the paravirtualizedmachine includes the network back-end driver and the block back-enddriver included in a control operating system 305, as described above.

Referring now to FIG. 3B, a block diagram depicts one embodiment of aplurality of networked computing devices in a system in which at leastone physical host executes a virtual machine. In brief overview, thesystem includes a management component 304 and a hypervisor 301. Thesystem includes a plurality of computing devices 100, a plurality ofvirtual machines 306, a plurality of hypervisors 301, a plurality ofmanagement components referred to as tools stacks 304, and a physicalresource 321, 328. The plurality of physical machines 100 may each beprovided as computing devices 100, described above in connection withFIGS. 1E-1H and 3A.

In greater detail, a physical disk 328 is provided by a computing device100 and stores at least a portion of a virtual disk 342. In someembodiments, a virtual disk 342 is associated with a plurality ofphysical disks 328. In one of these embodiments, one or more computingdevices 100 may exchange data with one or more of the other computingdevices 100 regarding processors and other physical resources availablein a pool of resources, allowing a hypervisor to manage a pool ofresources distributed across a plurality of physical computing devices.In some embodiments, a computing device 100 on which a virtual machine306 executes is referred to as a physical host 100 or as a host machine100.

The hypervisor executes on a processor on the computing device 100. Thehypervisor allocates, to a virtual disk, an amount of access to thephysical disk. In one embodiment, the hypervisor 301 allocates an amountof space on the physical disk. In another embodiment, the hypervisor 301allocates a plurality of pages on the physical disk. In someembodiments, the hypervisor provisions the virtual disk 342 as part of aprocess of initializing and executing a virtual machine 350.

In one embodiment, the management component 304 a is referred to as apool management component 304 a. In another embodiment, a managementoperating system 305 a, which may be referred to as a control operatingsystem 305 a, includes the management component. In some embodiments,the management component is referred to as a tools stack. In one ofthese embodiments, the management component is the tools stack 304described above in connection with FIG. 3A. In other embodiments, themanagement component 304 provides a user interface for receiving, from auser such as an administrator, an identification of a virtual machine306 to provision and/or execute. In still other embodiments, themanagement component 304 provides a user interface for receiving, from auser such as an administrator, the request for migration of a virtualmachine 306 b from one physical machine 100 to another. In furtherembodiments, the management component 104 a identifies a computingdevice 100 b on which to execute a requested virtual machine 306 d andinstructs the hypervisor 301 b on the identified computing device 100 bto execute the identified virtual machine; such a management componentmay be referred to as a pool management component.

Referring now to FIGS. 4A and 4B, some exemplary embodiments of avirtual application delivery controller 400 (also referred to herein asa “virtual appliance”) are shown and described. In brief overview, anyof the functionality and/or embodiments of the appliance 200 (i.e., anapplication delivery controller) described in connection with FIGS. 2Aand 2B may be deployed in any embodiment of the virtualized environment300 described above in connection with FIGS. 3A and 3B. Instead of thefunctionality of the application delivery controller being deployed inthe form of an appliance 200, such functionality may be deployed in anon-virtualized or virtualized environment 300 on any computing device100, such as a server 106. In particular, the functionality may bedeployed through software modules or components that execute on theserver 106.

Referring now to FIG. 4A, an exemplary embodiment of a virtual appliance400 operating on a hypervisor 301 of a server 106 is shown anddescribed. As with the appliance 200 of FIGS. 2A and 2B, the virtualappliance 400 may provide functionality for availability, performance,offload and security. For availability, the virtual appliance 400 mayperform load balancing between layers 4 and 7 of the network and/or mayperform intelligent service health monitoring. For performance increasesvia network traffic acceleration, the virtual appliance 400 may performcaching and/or compression. To offload processing of any servers 106,the virtual appliance 400 may perform connection multiplexing andpooling and/or SSL processing. For security, the virtual appliance 400may perform any of the application firewall functionality and/or SSL VPNfunction of appliance 200.

Any of the functionality of the appliance 200 as described in connectionwith FIG. 2A may be packaged, combined, designed or constructed in aform of the virtual appliance delivery controller 400 deployable as oneor more software modules or components. For example, with reference toFIG. 2A, any of the cache manager 232, policy engine 236, compression238, encryption engine 234, packet engine 240, GUI 210, CLI 212, shellservices 214 and health monitoring programs 216 may be designed orconstructed as a software module or component. These software modules orcomponents may be provided in the form of an installation package toinstall on a computing device. When deployed on a computing device, thevirtualized appliance delivery controller 400 may run on an operatingsystem of the computing device and/or in a virtualized environment 300.The virtualized appliance delivery controller 400 may execute in avirtualized environment 300 or non-virtualized environment on any server106. In the former situations, instead of using the encryption processor260, processor 262, memory 264 and network stack 267 of the appliance200, the virtualized appliance 400 may use any of these resources asprovided by the virtualized environment 300 or as otherwise available ona server 106.

Referring now to FIG. 4B, another embodiment of the virtualizedapplication delivery controller 400 is shown and described. In briefoverview, any one or more vServers 275A-275N may be operating orexecuting in a virtualized environment 300 of any type of computingdevice 100, such as an off-the-shelf server 106. Any of the modules orfunctionality of the appliance 200 described in connection with FIG. 4Bmay be designed or constructed to operate in either a virtualized ornon-virtualized environment of a server 106. Any of the vServer 275, SSLVPN 280, Intranet UP 282, Switching 284, DNS 286, acceleration 288, AppFW 280 and monitoring agent 197 may be packaged, combined, designed orconstructed in a form of application delivery controller 400 deployableas one or more software modules or components executable on a computingdevice and/or virtualized environment 300 of such a device.

In various embodiments, a server 106 may execute multiple virtualappliances 400. For example, the server 106 may execute multiple virtualmachines 306 a-306 n in the virtualized environment 300, and eachvirtual machine 306 may run the same or different embodiment of thevirtual appliance 400. Further, each virtual machine 306 may run one ormore virtual appliances 400. In multi-core processing systems, a singlecore may execute each virtual machine 306, or execution of the virtualmachines 306 may be dynamically allocated across multiple cores. In someembodiments, the server 106 may execute one or more virtual appliances400 on one or more virtual machines 306 on a core of a multi-coreprocessing system. In additional embodiments, the server 106 may executeone or more virtual appliances 400 on one or more virtual machines 306on each core of the multi-core processing system.

Referring now to FIG. 5A, an embodiment of an environment providing anapplication delivery fabric (ADF) 500 is shown and described. In briefoverview, a plurality of clients 102 access resources from one or moreservers 106 in a data center via a combination of one or more appliances200 and one or more virtual appliances 400A-400N deployed on any one ormore servers 106A-106N. In this embodiment, a centralized management andcommand center 510 provides a configuration, administration andmanagement tool for configuring, monitoring and administering theappliances 200 and any virtual appliances 400A-400N. One or moreappliance 200 may provide network-wide actions in the form of SSLoffloading, Denial of Service (Dos) mitigation and/or content switching.Further, the one or more appliances 200 may provide dynamic sourcerouting (DSR) for a mesh or adhoc network of one or more virtualappliances 400A-400N. The virtual appliance 400A-N may be deployedstatically or dynamically on one or more servers 106. These virtualappliances 400 may be dynamically deployed and undeployed in an adhocmanner as desired, on demand, automatic or manually. The virtualappliances 400 may each perform one or more application delivery andperformance functionality such as application specific load balancing,compression and/or application firewalling.

The application delivery fabric (ADF) 500 comprises any number ofinfrastructure components, systems, applications or services deployed ina network, such as a mesh or adhoc network, for delivering applicationsto users. In some cases, an ADF 500 refers to systems and processes fordelivering applications that make use of multiple, integrated productsdeployed in a mesh or ad-hoc network. The ADF 500 may secure, optimize,accelerate, and reliably deliver applications, information andresources, including front-end, mid-tier, support, and back-end systems.In some cases, an ADF 500 refers to the distributed infrastructurecomponents deployed along the line-of-sight between data centers andusers to ensure the successful, reliable delivery of any application toany user in any location.

As illustrated in FIG. 5A, the ADF 500 may comprise one or moreappliances 200 and one or more virtual appliances 400A-N for deliveringapplications from servers 106 in a data center to one or more clients102. In some embodiments, the ADF 500 includes other systems such as theapplication delivery system 190 of FIG. 1D and/or the WAN optimizationdevice 205 of FIG. 1C. In some embodiments, the ADF 500 includes aportion of a cloud computing service 575 in which servers 106, systemsand virtual appliances 400 are available and deployed for use,dynamically or otherwise (as described in reference to FIG. 5B). Each ofthe appliances, systems and virtual appliances 400 may be identified asa node in an adhoc or mesh network of the ADF 500. As appliances,systems and virtual appliances 400 are deployed and/or undeployed, theadhoc or mesh network changes and thus, the ADF 500 changes accordingly.

The appliances 200 and/or virtual appliances 400 may communicateinformation via any type and form of connection and/or protocol toprovide information regarding the topology, status, location, operationand performance of any node in the ADF 500. As deployment of nodes ofappliances 200, virtual appliances 400 or systems change (e.g., nodesare added or removed from the ADF 500), the nodes may provide updates tothe information regarding their topology, status, location, operationand performance. In some embodiments, one or more appliances 200 and/orvirtual appliances 400 may be configured as or act as a master node formaintaining or receiving such information. In some embodiments, one ormore appliances 200, such as a master node, may provide dynamic routing,such as dynamic source routing, to nodes in the ADF 500.

The ADF 500 may comprise any combination of heterogeneous or homogenoussystems, appliances 200 and virtual appliances 400. In some embodiments,the ADF 500 may be dedicated to a company or group of users. In otherembodiments, the ADF 500 may support multi-tenancy by supporting andbeing used for multiple companies or multiples groups of users. In someembodiments, the ADF 500 may comprise multiple appliances 200 of thesame type and/or configuration. In other embodiments, the ADF 500 maycomprise multiple appliances 200 of different types and/or differentconfigurations. In some embodiments, one or more of the deployed virtualappliances 400 may be of the same type and/or configuration. In otherembodiments, one or more of the deployed virtual appliances 400 may beof different types and/or different configurations. In some embodiments,a virtual appliance 400 may be deployed and/or configured for loadbalancing. In some embodiments, a virtual appliance 400 may be deployedand/or configured for acceleration, such as compression and/or caching.In various embodiments, a virtual appliance 400 may be deployed and/orconfigured for security, such as application firewall. In furtherembodiments, a virtual appliance 400 may be deployed and/or configuredfor offloading by performing connection pooling and multiplexing. Insome embodiments, the virtual appliance 400 may be configured for anycombination of load balancing, acceleration, security and/or offloading.

The ADF 500 may use any services and resources of or from a cloudcomputing service or environment 575. An IT infrastructure may extendfrom a first network—such as a network owned and managed by anenterprise—into a second network, which may be owned or managed by aseparate entity than the entity owning or managing the first network.Resources provided by the second network may be said to be “in a cloud”.Cloud-resident elements may include, without limitation, storagedevices, servers 106, databases, computing environments (includingvirtual machines 306 and desktops), and applications. In variousembodiments, one or more networks providing computing infrastructure onbehalf of customers may be referred to a cloud. In one of theseembodiments, a system in which users of a first network access at leasta second network including a pool of abstracted, scalable, and managedcomputing resources capable of hosting user resources may be referred toas a cloud computing environment. In another of these embodiments,resources may include, without limitation, virtualization technology,data center resources, applications, and management tools. In someembodiments, Internet-based applications (which may be provided via a“software-as-a-service” or “platform-as a service” model) may bereferred to as cloud-based resources. In other embodiments, networksthat provide users with computing resources, such as virtual machines306 or blades on blade servers, may be referred to as compute clouds. Instill other embodiments, networks that provide storage resources, suchas storage area networks, may be referred to as storage clouds. Infurther embodiments, a resource may be cached in a local network andstored in a cloud.

An ADF 500 and components of the ADF 500 may be configured, arranged,implemented or deployed in any manner for any logical grouping ofsupport to one or more companies, one or more users or groups of users,or one or more appliances, services or resources. In some embodiments,the ADF 500 may be dedicated to a company or group of users. In otherembodiments, the ADF 500 may support and be used for multiple companiesor multiples groups of users. In some embodiments, a first group of oneor more appliances 200 and/or virtual appliances 400 may be for a firstdata center. In some embodiments, a second group of one or moreappliances 200 and/or virtual appliances 400 may be for a second datacenter. In some embodiments, a first group of one or more appliances 200and/or virtual appliances 400 may be for a first application or service.In some embodiments, a second group of one or more appliances 200 and/orvirtual appliances 400 may be for a second application or service. Insome embodiments, a first group of one or more appliances 200 and/orvirtual appliances 400 may be for a first company. In some embodiments,a second group of one or more appliances 200 and/or virtual appliances400 may be for a second company. In some embodiments, a first group ofone or more appliances 200 and/or virtual appliances 400 may be for afirst group of users. In some embodiments, a second group of one or moreappliances 200 and/or virtual appliances 400 may be for a second groupof users.

The command center 510 may comprise any type and form of user interfacefor administering, configuring, maintaining, controlling and/ormonitoring of the ADF 500 and/or any components thereof. The commandcenter 510 may provide an interface for a user to identify, add, removeor modify any element of the topology, configuration, location andnetwork information for any of the nodes in the adhoc or mesh network ofthe ADF 500. The command center 510 may provide a user interface toidentify under what conditions or by what policies any of the virtualappliances 400 may be deployed and what functionality of these virtualappliances 400 are to be deployed. The command center 510 may provide auser an interface to deploy or undeploy a virtual appliance 400. Thecommand center 510 may provide a user interface to monitor theperformance and operational characteristics of the ADF 500 and/or anycomponents thereof.

Referring now to FIG. 5B, another embodiment of the ADF 500 is depicted.In brief overview, an ADF manager 550 may provide management of thedeployment and/or undeployment of any component of the ADF 500, such asa virtual appliance 400. Depending on the configuration, logic orpolicies of the ADF manager 550, one or more virtual appliances 400 maybe dynamically added or removed from the ADF 500. For example, the ADFmanager 550 may cause one or more virtual appliances 400 to be deployedin the ADF 500 to address additional capacity needs. In another example,an administrator may change policies that cause one or more virtualappliances 400 to be undeployed or deployed.

The ADF manager 550 may comprise any combination of hardware and/orsoftware to provide operations, functions, logic or business rules tomanage and/or control the ADF 500 or any components thereof. The ADFmanager 550 may comprise any application, program, service, library,task, script or set of executable instructions executing on a device.The ADF manager 550 may perform any of the operations described herein.The ADF manager 550 may operate, run or execute on any device within oroutside the nodes of the ADF. In some embodiments, the ADF manager 550runs on one of the appliances 200. In another embodiment, the ADF 500may operate on a stand-alone device, such as an ADF appliance orservice. The ADF manager 550 may communicate with, interface to or be apart of the command center 510. In such embodiments, the ADF manager 550may execute any administration, configuration or policies changes toreflect such changes in the ADF 500. The ADF manager 550 may alsomonitor the performance and/or operational characteristics of the ADF500 and components thereof and provide such information to the commandcenter 510.

The ADF manager 550 may be designed and constructed to deploy orundeploy a virtual appliance 400 in the ADF. The ADF manager 550 maydetermine when and how to deploy or undeploy a virtual appliance 400based on any command, configuration, rule or policy. The ADF manager 550may dynamically deploy or undeploy a virtual appliance 400 responsive toany command, configuration, rule or policy. The ADF manager 550 maydynamically deploy or undeploy a virtual appliance 400 responsive tomonitoring, detecting or identifying any operational and/or performancecharacteristics of the nodes of the ADF 500.

The ADF manager 550, such as configured on appliance 200, maydynamically change the topology of virtual appliances 400 responsive toany one or combination of a number of users, a number of connections, anumber of requests, use of bandwidth, transmission rates, round triptimes, response times, health of a service or virtual server and/or anystatistical measurement of any of above. In response to any changes ofthese performance and/or operational characteristics exceeding, meetingor falling under or within a predetermined threshold or range, the ADFmanager 550 may dynamically deploy or undeploy a virtual appliance 400.One or more policies may be specified or configured to set the thresholdand identify the action to perform with respect to a virtual appliance400. The ADF manager 550 may deploy or undeploy a virtual appliance 400responsive to a policy. In some embodiments, the policy may identify thetype, location and configuration of the virtual appliance 400. Thepolicy may identify the type, form and/or location of a virtualizedenvironment 300 to run the virtual appliance 400. The policy mayidentify the type, form and/or location of a server 106, processor orcore of a processor to run the virtual appliance 400. The policy mayidentify when to undeploy a virtual appliance 400.

The ADF manager 550 may communicate, interface or integrate with one ormore cloud computing services 575 to deploy and/or undeploy one or morevirtual appliances 400 on one or more servers 106 provided by the cloudcomputing services 575. For example, the ADF manager 550 may request acloud computing service 575 to deploy a virtual appliance 400. The ADFmanager 550 may provide the software of the virtual appliance 400 to thecloud computing service 575 to dynamically deploy on resources managedand provided by the cloud computing service 575.

Referring now to FIG. 6, an embodiment of an ADF 500 providingmulti-tenancy for a plurality of companies is depicted. In briefoverview, one or more ADFs 500 may be used to support and deliverapplications, computing environments and/or resources to multiplecompanies and their users, such as company A, company B and company C.One or more appliances 200 may be deployed to service each of thesecompanies. For example, one appliance 200 may receive network trafficfrom computing devices of these companies and determine which virtualappliances 400 will service the traffic. One or more virtual appliances400 may be deployed in conjunction with the appliance 200 to provideservices to each of the companies. For example, virtual appliance 400Amay be dedicated to company A, virtual appliance 400C to company C, andvirtual appliance 400B to both Company A and Company C.

With the use of virtualized environments 300, a single server 106 mayhost a plurality of virtual appliances 400 via a plurality of virtualmachines 306. As each virtualized environment 300 may provide a distinctseparation of resource use of the server 106 via a virtual machine 306,each of the virtual appliances 400 may be dedicated to a differentcompany, users, service or application without conflict to any anothervirtual appliance 400 in a different virtualized environment 300. Inthis manner, one or more virtual appliances 400 may be deployed on adevice that has multiple tenants. For example, virtual appliance 400Band/or server 106 may comprise a first virtual appliance 400A on a firstvirtual machine 306A for a first company and a second virtual appliance400B on a second virtual machine 306B for a second company. Thesevirtual machines 306 may either be in the same virtualized environment300 or different virtualized environments 300.

With the flexibility of deploying virtual appliances 400 on virtualmachines 306 hosted on one or more servers 106, the ADF 500 may supportmultiple tenants, such as multiple companies. Furthermore, an ADFmanager 550 may dynamically change the topology of the ADF 500responsive to performance and/or operational characteristics of theportion of the ADF 500 corresponding to a specific tenant. For example,responsive to capacity or policy changes, the ADF manager 550 may deployor undeploy a virtual appliance 400 for a company while leavingunchanged virtual appliances 400 for another company. In otherembodiments, one or more ADF managers 550 may manage multiple ADFs 500that overlay the same or common infrastructure components, such as thesame appliances 200 and virtual appliances 400 being used for multipletenants. For example, appliance 200 and virtual appliance 400A may bepart of a first ADF for company A. Appliance 200 and virtual appliance400B may be part of a second ADF for company B, and appliance 200 andvirtual appliances 400B and 400C may be part of a third ADF for companyC.

Referring now to FIG. 7, another embodiment of an ADF 500 delivered viaa cloud computing service 575 is depicted. In brief overview, a cloudcomputing service provider 575 may deploy an ADF 500 and any appliancesand/or virtual appliances of the ADF 500 to address changes in operationand performance, such as capacity, level of service and demand. Forexample, the cloud computing service 575 may be using an appliance 200and virtual servers 400A-400N at a first data center for servicing onetenant or user. Based on changes in operations, the cloud computingservice 575 may deploy one or more virtual appliances 400 at a seconddata center to handle these changes. For example, the load on the firstdata center may reach a threshold and the cloud computing service 575may deploy virtual appliances 400 at the second data center to handlethe additional load. In this manner, the cloud computing service 575 mayleverage the flexible, extensible and dynamic nature of the ADF 500 tomore effectively and manage its operations in servicing and providing alevel of service to users of their cloud computing service 575.

With the systems and methods of the ADF 500, the virtual appliances 400,and the virtual appliances 400 operating on virtual machines 306 and/ormultiple cores and processor, these systems provide a dynamic, flexibleand extensible solution for scaling, balancing and using resources moreefficiently and effectively for delivering applications and resources toa wide range of users and technology environments. With the ADF 500described herein, application delivery controllers can be deployedon-demand and to any location and when and where most needed.Enterprises and administrators can leverage the ADF 500 to provide moreefficient use of resources, including dynamic allocations/re-allocationof resources, and flexible re-purposing of resources that leveragedynamic data center processes.

It should be understood that the systems described above may providemultiple components of any of the components described herein and thesecomponents may be provided on either a standalone machine or, in someembodiments, on multiple machines in a distributed system. In addition,the systems and methods described above may be provided as one or morecomputer-readable programs embodied on or in one or more articles ofmanufacture. The article of manufacture may be a floppy disk, a harddisk, a CD-ROM, a flash memory card, a PROM, a RAM, a ROM, or a magnetictape. In general, the computer-readable programs may be implemented inany programming language, such as LISP, PERL, C, C++, C#, PROLOG, or inany byte code language such as JAVA. The software programs may be storedon or in one or more articles of manufacture as object code.

Referring now to FIG. 8, an embodiment of a method for deploying avirtual application delivery controller 400 is shown and described. Themethod includes performing, by one or more application deliverycontroller appliances intermediary to a plurality of clients and aplurality of servers, a plurality of application delivery controlfunctions on network traffic communicated between the plurality ofclients and the plurality of servers (step 801). The method alsoincludes deploying a virtual application delivery controller on a deviceintermediary to the plurality of clients and the plurality of servers(step 803). The method also includes performing, by the virtualapplication delivery controller executing on the device, one or more ofthe plurality of application delivery control functions on networktraffic communicated between the plurality of clients and the pluralityof servers (step 805).

One or more application delivery controller appliances intermediary to aplurality of clients and a plurality of servers performs a plurality ofapplication delivery control functions on network traffic communicatedbetween the plurality of clients and the plurality of servers (step801). The one or more appliances 200 may perform application deliverycontrol functions on network traffic received from clients. In someembodiments, the appliances 200 may perform these functions on networktraffic routed from a master node. The appliances 200 may performfunctionality for availability, performance, offloading, and/orsecurity, according to any of the methods described in reference toFIGS. 4A-5A. The appliances 200 may also perform dynamic service routingon the network traffic to redirect the traffic to servers 106 withresources of interest to the users of the clients.

In many embodiments, the appliances 200 communicate information aboutthe their operation and/or performance. The appliances 200 transmit thisinformation to any component, such as a master node, that aggregatesinformation about the operation and performance of nodes in an ADF 500.In some embodiments, the component may be an ADF manager 550 or acommand center 515, such as the managers 550 and command centers 515described in reference to FIGS. 5A and 5B. The appliances 200 mayreceive information about the operation and/or performance of otherappliances 200 and transmit the information to the ADF manager 550 orcommand center 515. With respect to this method, any operation describedherein as performed by an ADF manager 550 may be performed by a commandcenter 515, and vice versa.

In some embodiments, a virtual application delivery controller (ADC) isdeployed on a device, such as a device intermediary to a plurality ofclients and the plurality of servers (step 803). The virtual ADC may bedeployed with or operate in conjunction with the one or more applicationdelivery controller appliances. In some embodiments, multiple virtualADCs are deployed on the same device. In some embodiments, multiplevirtual ADCs are deployed on a plurality of devices. In someembodiments, a virtual ADC is deployed on an appliance. In someembodiments, a virtual ADC is deployed on a core of a multi-coreappliance. In some embodiments, a virtual ADC is deployed on a server.In some embodiments, a virtual ADC is deployed on a server in a serverfarm. In some embodiments, a virtual ADC is deployed on a server from acloud computing service or network.

An ADF manager 550 or centralized command center 515 may determine todeploy the virtual application delivery controller 400. In manyembodiments, an ADF manager 550 or command center 515 uses a policy todecide when to deploy a virtual appliance 400 on a device. The ADFmanager 550 or command center 515 may include default policies to guidesuch deployment. In some embodiments, a user, such as an ADFadministrator, may customize the policies. For example, a user mayspecify to a command center 515 the conditions under which virtualappliances 400 shall be deployed. The command center 515 may monitor thenodes in the ADF 500 deploy virtual appliances 400 when one or more ofthe conditions are fulfilled. In alternative embodiments, the commandcenter 515 may transfer these conditions to an ADF manager 550 thatmonitors the nodes in the application delivery fabric 500. When the ADFmanager 550 detects that the conditions have been fulfilled, the ADFmanager 550 may deploy a virtual appliance 400. In any of theseembodiments, the policy or conditions may relate to the operation and/orperformance of the nodes in the ADF 500.

The ADF manager 550 may select a device to host the virtual appliance400. For example, the ADF manager 550 may select the device from apredetermined group of devices, such as a server farm at a data center.The ADF manager 550 may store the identities of devices reserved forhosting virtual appliances 400 or consult an external database for theidentities of such devices. In some embodiments, the ADF manager 550 mayrequest a cloud service 575 to execute the virtual application deliverycontroller 400 on resources provided by the cloud service 575. The cloudservice 575 may allocate a device to host the virtual appliance 400 andtransmit the identity of the device to the ADF manager 550.

The virtual appliance 400 may be deployed via software modules installedon the selected device. The software modules may be stored in anylocation, such as the ADF manager 550, command center 515, softwaredatabase, or an appliance 200. In various embodiments, one or more ofthe plurality of application delivery control functions for the virtualappliance 400 may be configured for deployment. For example, a virtualappliance 400 may be configured for load balancing, acceleration,security, offloading, or any combination thereof.

In some embodiments, when the ADF manager 550 determines a virtualappliance 400 should be deployed, the ADF manager 550 may transmit acopy of software modules to the selected device for deployment thereon.In another example, the ADF manager 550 may transmit an instruction tothe selected device to deploy a virtual appliance 400, and the selecteddevice may request the software modules for the virtual appliance 400from a software database. In further examples, the ADF manager 550 maytransmit an instruction to the appliance 200 closest to the selecteddevice to transmit a copy of the software modules to the device. In yetanother example, the ADF manager 550 may transmit the software modulesto the cloud service 575, and the cloud service 575 deploys the moduleson the device allocated for the virtual appliance 400.

The software modules of the virtual appliance 400 may be installed toexecute in a non-virtualized environment of the device. In some of theseembodiments, the software modules may execute on the operating system ofthe device. In other examples, the software modules are deployed in avirtualized environment 300 provided by the device. In one such example,the software modules may execute on a virtual operating system hosted bythe device. In further examples, the virtual appliance 400 may bedeployed to execute on a virtual machine 306 provided by the device ordeployed to execute as a virtual machine 306 on the device. In someembodiments, the software modules may include any of the virtualmachines or virtualized environment for the virtual ADC.

Deploying a virtual appliance 400 may change the topology of the ADF500. After a virtual appliance 400 is deployed on a device, the virtualappliance 400 begins communicating information about its topology,status, location, operation, and/or performance. A virtual appliance 400may transmit such information to an ADF manager 550, a command center, amaster node, or any component that monitors the nodes of the ADF 500.

After the virtual application delivery controller is deployed on adevice intermediary to the plurality of clients and the plurality ofservers (step 803), the virtual application delivery controllerexecuting on the device performs one or more of the plurality ofapplication delivery control functions on network traffic communicatedbetween the plurality of clients and the plurality of servers (step805).

The virtual appliance 400 may perform the one or more of the pluralityof application delivery control functions on a first portion of networktraffic concurrently to the one or more application delivery controllerappliances 200 performing the plurality of application delivery controlfunctions on a second portion of network traffic. In these embodiment,the virtual appliance 400 operates like an appliance 200 functioning inparallel with other application delivery controller appliances 200 inthe ADF 500, servicing a portion of the network traffic the ADF 500receives from clients. Thus, the virtual appliance 400 may be configuredto perform the same application delivery control functions as theappliances 200. The virtual appliance 400 may perform any of thesefunctions before transmitting the network traffic to a server 106 thatservices the network traffic.

The virtual appliance 400 may perform a first application deliverycontrol function on a first portion of network traffic subsequent to anapplication delivery controller appliance 200 performing a secondapplication delivery control function on the first portion of networktraffic. In these embodiments, the appliance 200 first performs at leastone application delivery control function on the network traffic. Forexample, the appliance 200 may perform network-wide actions such as ofSSL offloading, Denial of Service (Dos) mitigation and/or contentswitching. Then, the appliance 200 routes the network traffic to thevirtual appliance 400 via, for example, DSR. The virtual appliance 400performs at least one other application delivery control function on thenetwork traffic, such as application specific load balancing,compression, and/or application firewalling. In these embodiments, thevirtual appliance 400 may perform application delivery control functionsdistinct from the functions of the appliance 200. In particular, thevirtual appliance 400 may perform one or more application deliverycontrol functions that are performed subsequently to the applicationdelivery control functions performed by the appliances 200.

In embodiments where the application delivery fabric is composed solelyof virtual appliances, a virtual appliance 400 a may perform a firstapplication delivery control function on a first portion of networktraffic subsequent to another virtual appliance 400 b performing asecond application delivery control function on the first portion ofnetwork traffic. In these embodiments, a virtual appliance 400 may beconfigured to perform functions delegated to application deliverycontrollers. For example, a virtual appliance 400 b may performnetwork-wide actions such as of SSL offloading, Denial of Service (Dos)mitigation and/or content switching. Then, the virtual appliance 400 bmay route the network traffic to another virtual appliance 400 a thatperforms additional functions, such as application specific loadbalancing, compression, and/or application firewalling.

Referring now to FIG. 9, an example embodiment of a method for managinga plurality of application delivery controllers of an applicationdelivery network is shown and described. The method includes monitoring,by an application delivery fabric (ADF) manager executing on a device,an application delivery fabric (ADF) network comprising a deployment ofa plurality of application delivery controllers intermediary to aplurality of a clients and a plurality of servers (step 901). The methodalso includes determining, by the ADF manager responsive to monitoring,that an operational or performance characteristic of the ADF networkfails a corresponding threshold (step 903). The method also includesdynamically deploying, by the ADF manager responsive to thedetermination, a virtual application delivery controller as part of theADF network (step 905).

In operation, an application delivery fabric (ADF) manager executing ona device monitors an application delivery fabric (ADF) networkcomprising a deployment of a plurality of application deliverycontrollers intermediary to a plurality of a clients and a plurality ofservers (step 901). The ADF manager 550 may execute on any device asdescribed in reference to FIGS. 5A and 5B. Further, the ADF manager 550may monitor the ADF network 500 according to any method described inreference to FIGS. 5A and 5B. In particular, the ADF manager 550 may beconfigured to receive information from each node in the ADF network 500about the node's topology, status, location, operation, and/orperformance. As such, when each node is deployed in the ADF network 500,the node may be configured to transmit such information to the ADFmanager 550. In various embodiments, a node may transmit informationsuch as its number of users, number of active connections, responsetimes, bandwidth rates, and/or transmission rates.

In some embodiments, a node may transmit the information atpredetermined intervals of time. In additional embodiments, a node maytransmit the information in response to significant events. For example,when a node detects that its performance has fallen beneath a threshold,the node may transmit a signal to the ADF manager 550 indicating thisevent. In another example, when a node detects that its load hasincreased by a predetermined percentage or reached a predeterminedcapacity, the node may indicate this event to the ADF manager 550.

Further, the ADF manager 550 may transmit probes to a node to obtain anytype of information at any time. If the ADF manager 550 has not receivedinformation from a node after a predetermined interval of time haslapsed, the manager 550 may transmit a probe inquiring about the statusof the node. If the probe times out without a response, the ADF manager550 may conclude that the node is non-operational and/or non-functional.If the ADF manager 550 receives information that multiple nodes have lowbandwidth rates, the ADF manager 550 may probe the nodes for informationabout their active connections with a view towards consolidating theconnections on one node.

The ADF network 500 may refer to any of the embodiments described inreference to FIG. 5A. The ADF manager 550 may establish one or moreapplication delivery controller appliances 200 and/or one or morevirtual application delivery controllers 400 as part of the ADF network500. In some embodiments, the ADF network 500 may include nodescorresponding to one or more virtual appliances 400 intermediary to aplurality of clients 102 and a plurality of servers 106. These virtualappliances 400 may provide the same functionality as the appliances 200.In various embodiments, the virtual appliances 400 may be intermediaryto the plurality of appliances 200 and the plurality of servers 106. Theappliances 200 perform at least one application delivery controlfunction on network traffic and route the network traffic to the virtualappliances 400. The virtual appliances 400 perform additionalapplication delivery control functions on the network traffic beforerouting the network traffic to the servers 106. In further embodiments,the ADF network 500 may include a portion of at least one cloudcomputing service 575. The cloud computing services 575 includesresources, such as servers 106 or other computing devices, that may bedynamically deployed for the ADF network's 500 use.

Responsive to the application delivery fabric (ADF) manager monitoringan application delivery fabric (ADF) network, the ADF manager maydetermine that an operational or performance characteristic of the ADFnetwork fails a corresponding threshold (step 903). The ADF manager 550may aggregate the information received from the nodes to calculate anoperational or performance characteristic of the ADF network 500. Insome embodiments, the ADF manager 550 aggregates the information onlyfrom appliances 200. In other embodiments, the ADF manager 550aggregates information from both appliances 200 and virtual appliances400.

In various embodiments, the operational or performance characteristicmay correspond to a number of users using the ADF network 500 or anumber of connections an ADF network 500 is servicing. The operationalor performance characteristic may correspond to the response times ofservers 106 via the appliances 200 and/or virtual appliances 400 in theADF network 500. The operational or performance characteristics maycorrespond to bandwidth and/or transmission rates via the appliances 200and/or virtual appliances 400. The ADF manager 550 may store thresholdscorresponding to any of these operational or performancecharacteristics.

When the ADF manager 550 aggregates received information from the nodesto calculate an operational or performance characteristic of the ADFnetwork 500, the ADF manager 550 may compare the characteristic to thecorresponding threshold. If the characteristic exceeds the correspondingthreshold, the ADF manager 550 may determine that the characteristic ofthe ADF network 500 fails the threshold.

Responsive to the ADF manager 550 determines that an operational orperformance characteristic of the ADF network fails a correspondingthreshold (step 903), the ADF manager 550 may dynamically deploy orundeploy a virtual application delivery controller as part of the ADFnetwork (step 905).

The ADF manager 550 may deploy the virtual appliance 400 according to apolicy when the ADF network 500 fails a threshold. The ADF manager 550may select a device to deploy the virtual appliance 400 according to anymethod described in reference to FIG. 8. In some embodiments, the ADFmanager 550 may dynamically deploy the virtual appliance 400 via a cloudservice. The ADF manager 550 may provide a request to deploy a virtualappliance 400 to a cloud service. In some embodiments, the requestincludes the software modules for deploying the virtual appliance 400.In response, the cloud service allocates a server 106 from itsresources, installs the software modules therein, and transmits theidentity of the server 106 to the ADF manager 550. The ADF manager 550may add the cloud service's server 106 to the ADF network 500 and beginreceiving information from this server 106.

In some embodiments, in response to the ADF manager's 550 request todeploy a virtual appliance 400, the cloud service 575 allocates a server106 and transmits the identity of the server 106 to the ADF manager 550.Then, the ADF manager 550 transmits the software modules for deployingthe virtual appliance 400 to the cloud service 575, and the cloudservice 575 installs the modules on the server 106. In some embodiments,the ADF manager 550 communicates directly with the allocated server 106to deploy the virtual appliance 400 thereon. The ADF manager 550 addsthe server 106 to the ADF network 500 and begins receiving informationfrom the server 106.

After the ADF manager 550 dynamically deploys a virtual applicationdelivery controller 400 as part of the ADF network 500, the ADF manager550 may undeploy a virtual application delivery controller 400 from theADF network 500, such as responsive to monitoring or administration. Asthe ADF manager 550 continues to receive information from the nodes inthe ADF network 500, the ADF manager 550 may update operational orperformance characteristics of the ADF network 500. Based on thesecharacteristics, the ADF manager 550 may determine that networkcontraction is appropriate and undeploy a virtual appliance 400.

In many embodiments, to make this determination, the ADF manager 550compares the operational or performance characteristics of the ADFnetwork 500 with the operational or performance capacities of thenetwork 500. As the ADF manager 550 deploys more appliances 200 orvirtual appliances 400, the ADF manager 550 adds the operational orperformance capacities of the newly deployed components to the netcapacities of the pre-existing ADF network 500. For example, if the ADFmanager 550 deploys a virtual appliance 400 capable of serving 4000users, the ADF 500 increases the number of users the ADF network 500 mayservice by 4000. In this manner, the ADF manager 550 may track thecapacity of the deployed network 500.

The ADF manager 550 may undeploy at least one virtual appliance 400 ifthe operational or performance characteristics of the ADF network 500are less than a predetermined percentage of the network capacity. Forexample, if the ADF manager 550 determines the ADF network 500 isoperating at 75% of its capacity according to any of the metricsdescribed herein, the ADF manager 550 may undeploy at least one virtualappliance 400. In some embodiments, the ADF manager 550 may undeploy atleast one virtual appliance 400 if the operational or performancecharacteristics of the ADF network 500 warrant consolidation of networktraffic among fewer appliances and virtual appliances. For example, ifremoval of a virtual appliance 400 and consolidation of the networktraffic among the remaining appliances permits the ADF network 500 tofunction within a predetermined range of capacities, the ADF manager 550may undeploy at least one virtual appliance 400. The ADF manager 550 mayselect any virtual appliance 400 to undeploy. In some embodiments, theADF manager 550 may select a virtual appliance 400 operating at thelowest capacity. The virtual appliance's 400 network traffic isrerouting to neighboring virtual appliances 400 before undeployment. Inmany embodiments, the ADF manager 550 may select a virtual appliance 400with the smallest capacity. The ADF manager 550 may continue to undeployvirtual appliances 400 in order of increasing capacity until the ADFnetwork 500 reaches a desired overall capacity. In this manner, byundeploying virtual appliances 400 with small capacities first, the ADFmanager 550 minimizes the number of virtual appliances in the ADFnetwork 500.

Although the systems and methods herein may describe an applicationdelivery fabric of application delivery controller appliances andvirtual application delivery controllers, in various embodiments, thefabric may include solely a plurality of embodiments of virtualapplication delivery controllers, as would be appreciated by one ofordinary skill in the art.

In view of the structure, functions and apparatus of the systems andmethods described here, the present solution provides efficient andintelligent system for deploying virtual appliances. Having describedcertain embodiments of methods and systems for deploying virtualappliances, it will now become apparent to one of skill in the art thatother embodiments incorporating the concepts of the invention may beused. Therefore, the invention should not be limited to certainembodiments, but rather should be limited only by the spirit and scopeof the following claims:

What is claimed:
 1. A system for deploying a virtual applicationdelivery controller on a virtualized environment of a device of one ormore devices as part of an application delivery fabric (ADF) network,comprising: a first device of the one or more devices, comprising one ormore processors and intermediary to a plurality of clients and aplurality of servers, the first device configured to perform a pluralityof application delivery control functions on network trafficcommunicated between the plurality of clients and the plurality ofservers; a command center executable on the one or more devices andconfigured to deploy, responsive to monitoring performancecharacteristics of at least the first device, one or more virtualapplication delivery controllers on one or more other devices, whereinthe command center is further configured to establish the one or morevirtual application delivery controllers to communicate with the firstdevice to be part of the application delivery fabric (ADF) network; avirtual application delivery controller configured to be deployed, bythe command center responsive to a threshold capacity of the firstdevice being reached, on a second processor of a second device of theone or more other devices to perform one or more of a plurality ofapplication delivery control functions, and to be undeployed from thesecond device, by the command center responsive to monitored performancecharacteristics indicating that demand for resources of the ADF networkhas dropped below a predetermined threshold; and wherein the firstdevice and the virtual application delivery controller on the seconddevice are configured to perform at least the one or more applicationdelivery control functions on network traffic communicated between theplurality of clients and the plurality of servers.
 2. The system ofclaim 1, wherein the virtual application delivery controller is furtherconfigured to execute on a virtual machine of the second device.
 3. Thesystem of claim 1, wherein the second device to execute the virtualapplication delivery controller is a device of a cloud service.
 4. Thesystem of claim 1, wherein the virtual application delivery controlleris further configured to execute on a non-virtualized environment of thesecond device.
 5. The system of claim 1, wherein the command center isfurther configured to deploy the virtual application delivery controllerto support a tenant in a multi-tenant deployment of a network ofapplication delivery controllers intermediary to the plurality ofclients and the plurality of servers.
 6. The system of claim 1, whereinthe virtual application delivery controller is further configured to beconfigured with at least one application delivery control functiondifferent from the one or more application delivery control functions.7. The system of claim 1, wherein virtual application deliverycontroller is further configured to perform the one or more of theplurality of application delivery control functions on a first portionof network traffic concurrently to the first device performing theplurality of application delivery control functions on a second portionof network traffic.
 8. The system of claim 1, wherein the virtualapplication delivery controller is further configured to perform a firstapplication delivery control function on a first portion of networktraffic subsequent to the first device performing a second applicationdelivery control function on the first portion of network traffic.
 9. Asystem for dynamically deploying a virtual application deliverycontroller as part of a network of a plurality of application deliverycontrollers, comprising: a first processor; a second processor; amanager executable on the first processor of a first device configuredto monitor performance characteristics of a network of a plurality ofapplication delivery controllers executing on a plurality of devicesintermediary to a plurality of clients and a plurality of servers andconfigured to deploy, responsive to monitoring the network of aplurality of application delivery controllers, one or more virtualapplication delivery controllers on one or more other devicesintermediary to the plurality of clients and the plurality of servers toprovide additional application delivery controllers in the network ofthe plurality of application delivery controllers, wherein the manageris further configured to establish the additional virtual applicationdelivery controller to communicate with the first device to be part ofthe network of a plurality of application delivery controllers; andwherein the manager is configured to determine, responsive to monitoringthe network of the plurality of application delivery controllers, that aperformance characteristic of the network of the plurality ofapplication delivery controllers exceeds a threshold, and responsive tothe determination, to deploy a virtual application delivery controllerof the one or more virtual delivery controllers on a second processor ofa second device of the plurality of devices, intermediary to theplurality of clients and the plurality of servers, as part of thenetwork of the plurality of application delivery controllers executingon the plurality of devices and performing one or more applicationdelivery control functions on network traffic between the plurality ofclients and the plurality of servers, and to undeploy the virtualapplication delivery controller from the second device responsive to theperformance characteristic of the network of the plurality ofapplication delivery controllers falling below the threshold.
 10. Thesystem of claim 9, wherein the first device is one of intermediary tothe plurality of clients and servers or is part of the network of theplurality of application delivery controllers.
 11. The system of claim9, wherein the manager is further configured to determine, responsive tomonitoring, that a number of users of the plurality of applicationdelivery controllers exceeds the threshold.
 12. The system of claim 9,wherein the manager is further configured to determine, responsive tomonitoring, that a number of connections the plurality of applicationdelivery controllers exceeds the threshold.
 13. The system of claim 9,wherein the manager is further configured to determine, responsive tomonitoring, that response times of servers via the plurality ofapplication delivery controllers exceeds the threshold.
 14. The systemof claim 9, wherein the manager is further configured to determine,responsive to monitoring, that a bandwidth rate via the plurality ofapplication delivery controllers exceeds the threshold.
 15. The systemof claim 9, wherein the manager is further configured to determine,responsive to monitoring, that a transmission rate via the plurality ofapplication delivery controllers exceeds the threshold.
 16. The systemof claim 9, wherein the manager is further configured to change atopology of the network of the plurality of application deliverycontrollers by one of deploying or undeploying the virtual applicationdelivery controller.